Birds doi: 10.3390/birds7020028

Authors: Camila Alampe Cardoso Roberto Sargo Luís Sousa Filipe Silva Isabel Pires

Wild birds are increasingly exposed to anthropogenic threats that compromise population viability. Wildlife rehabilitation centers provide valuable data to monitor these pressures and their conservation implications. This retrospective study analyzed wild bird admissions to the Wildlife Recovery Center of the University of Trás-os-Montes and Alto Douro (CRAS-UTAD) in northern Portugal between January 2007 and October 2025. A total of 5090 birds from 135 species and 44 families were admitted. Causes of admission were grouped into 11 categories, and outcomes into 7. Admissions increased over time, rising from approximately 160 birds in 2007 to more than 430 in 2025, although the overall temporal trend was not statistically significant. Birds of prey were the most frequently admitted group, particularly Strix aluco (9.16%) and Buteo buteo (8.00%). The most common causes of admission were orphaned birds (26.2%), followed by seizures from illegal captivity (12.2%) and collisions (5.0%). Overall, 43.2% of birds were released, while 29.4% died and 18.3% were euthanized. Admission cause was strongly associated with outcome, with electrocution showing the poorest prognosis and seizure from illegal captivity the highest probability of release. These findings highlight the major impact of human activities on wild bird morbidity and mortality and reinforce the importance of rehabilitation centers as sentinels for conservation and mitigation strategies.

Birds doi: 10.3390/birds7020027

Authors: James Alexander Kempton Attila Balázs Yoel Bessoran Yohanna Dalimunthe Anik Budhi Dharmayanthi Jared Diamond David Bishop Yolanda Duwiri Amir Hamidy Tri Haryoko Charlie Danny Heatubun Edward Glorious Excelsa Heatubun Melias Heluka John Imbenai Gustiar Nurul Inayah Mohammad Irham Georgios Karris Henderina Keiluhu Iain Kobak Malcolm Kobak Gison Morib Pascal Norotouw Ruben Penggu Dewi Prawiradilaga Mochtar Tanassy Heron Yando John Yalak Sili Yalak Leonidas-Romanos Davranoglou

New Guinea, the world’s largest tropical island, supports the planet’s richest insular avifauna. Large areas of New Guinea remain poorly surveyed, however, in part due to the island’s challenging terrain. In hard-to-access areas, like many mountainous parts of New Guinea, automated surveying tools, like camera traps, may be especially helpful to address the survey deficit. Here we present the results of a camera-trap survey of the avifauna of the Cyclops Mountains, a range in New Guinea’s western, Indonesian provinces (Indonesian Papua). To our knowledge, our results represent only the second published camera-trap survey of birds from Indonesian Papua. We deployed 73 camera traps along an elevation gradient (143–1963 m) of the Cyclops Mountains for 11,869 camera-trap nights, recording 22 bird species from 1696 independent detections. Our species list is, to our knowledge, the first to include observations from the upper northern slopes of the Cyclops Mountains. It documents the first record of Masked Bowerbird (Sericulus aureus) in the range and provides photographic rediscoveries of two ‘lost’ species: Mayr’s Honeyeater (Ptiloprora mayri) and Mayr’s Forest Rail (Rallicula mayri). We also report substantial elevation range extensions for several species, including numerous records of Northern Cassowary (Casuarius unappendiculatus) over 1000 m above its historically known elevation ceiling. These findings provide new insights into species distributions and ecological flexibility in New Guinea’s montane systems, highlighting the potential for previously undocumented biodiversity in under-surveyed regions. Although camera traps detected fewer species than traditional ornithological methods, they were effective in documenting several elusive, ground-dwelling bird species, highlighting their value as a complementary tool for ornithological research in challenging terrain like New Guinea. Finally, we use our data to publish an updated bird species checklist for the Cyclops Mountains.

Birds doi: 10.3390/birds7020026

Authors: Reuven Yosef

Solitary living is an evolutionarily widespread yet comparatively under-theorized social system, despite its occurrence across diverse animal taxa. Shrikes (family Laniidae) are small predatory passerines that combine raptorial behavior, strong territoriality, and predominantly solitary space use, making them a powerful model for examining the ecology and evolution of solitary living. Here, I synthesize published work on shrike behavioral ecology and explicitly link these traits to the costs and benefits of a solitary lifestyle. I argue that shrikes exemplify how solitary species can offset the absence of social buffering through cognitive innovation, finetuned habitat selection, and flexible yet tightly bounded sociality. I then compare shrike ecology to solitary mammals and reptiles, highlighting convergent patterns in resource dispersion, spatial memory, risk management, and juvenile dispersal. I further examine how anthropogenic pressures, such as habitat fragmentation, climatic instability, and urbanization, interact with solitary life histories and review evidence from management interventions in both European farmland and North American systems that demographic recovery is achievable but remains contingent on addressing broader land-use conflicts and sources of adult mortality. Finally, I outline five interconnected research priorities—spanning cognitive ecology, trophic interactions, movement ecology, genomics, and formal comparative analyses—that would move shrike research from its current observational foundation toward a more experimental, mechanistic, and phylogenetically informed programme. By reframing shrikes as a model taxon for solitary living, this review aims to integrate avian behavioral ecology into broader comparative frameworks of social organization, cognition, and resilience under global change.

Birds doi: 10.3390/birds7020025

Authors: Xuemeng Zhou Fang Fang Junxiang Huang Ruiling Liu Aiwu Jiang

Bird migration is an awe-inspiring phenomenon that causes massive global shifts in bird distributions twice a year. To understand the evolution of this phenomenon, it is crucial to know the mortality costs of these journeys. Extreme weather-related events can lead to abnormally high mortality rates among migratory birds, while high mercury concentration may reduce the survival of songbirds in the field, especially for the long-distance migrant insectivores. Yet the specific vulnerability factors remain largely unknown. We collected the opportunistic dead Eastern Red-rumped Swallows (Cecropis daurica) in a mass-mortality event caused by a cold wave in autumn migration in Southern China. Mercury concentration in their tail feathers is 0.57 ± 0.37 µg g−1, lower than the established toxicity threshold for birds. The claws’ hydrogen stable isotopic (δD) values ranged from −116 to −78 ‰, with a mean of (−88.00 ± 8.22) ‰. Stable hydrogen isotopes indicated broad origins for the Eastern Red-rumped Swallows, ranging from ~30° N to ~62° N and ~10° E to ~150° E. Considering subspecies ranges, most of the dead swallows likely came from their almost furthest breeding sites. Our results indicated the primary cause of the mass-mortality event was likely fatigue or starvation resulting from long-distance flight during an extreme cold wave. Mercury exposure may not be the main direct cause of death.

Birds doi: 10.3390/birds7020024

Authors: Zlatozar Nikolaev Boev

For the first time, an attempt has been made to comprehensively summarize data on the past distribution of bustards on the territory of Bulgaria based on their fossil and subfossil finds. The collected data refer to a total of 32 Quaternary localities (natural and of anthropogenic origin), of which three are Pleistocene and 29 of Holocene age. The earliest locality of an otidid identified to the species level dates back to 2.4 million years ago. A total of three species have been identified. Among them, one species, Khosatzki’s Houbara (Otis aff. khosatzkii), has disappeared from the modern fauna of the country. Great Bustard (Otis tarda) was found in 20 Quaternary localities, Little Bustard (Tetrax tetrax) in eight, Otis tarda/Tetrax tetrax in two, Khosatzki’s Houbara in one and Otididae gen. in one locality. Chronostratigraphically both Great Bustard and Little Bustard were spread from Greenlandian to Meghalayan (i.e., last ca. 117,000 ya), while the earliest Khosatzki’s Houbara is known only from Gelasian (2.23–2.40 Mya). All finds originated from localities at between 20 and 670 m. a.s.l. in plains, lowlands and low hills. The presence of extant species of bustards on the territory of Bulgaria is rather a post-Pleistocene (Holocene) phenomenon. Besides their primary use as a source of meat for food, bustards in Bulgaria were also used as a source of materials for tool making by ancient people.

Birds doi: 10.3390/birds7020023

Authors: Guy Beauchamp Sahas Barve

Vigilance is used to detect distant threats in many species of birds. Allocation of time to vigilance is shaped by the social and physical environment of individuals, but little research has focused on how weather variables affect vigilance. Wind speed, in particular, can influence vigilance by decreasing manoeuvrability during escape, increasing energy costs or by decreasing the ability to communicate and assess risk. We examined how wind speed influenced vigilance in sentinels of a cooperative breeder, the Florida Scrub-Jay (Aphelocoma coerulescens). Sentinels in this species occupy vantage points to monitor their surroundings and can devote all their time to vigilance during sentinel bouts. We found that head turns in sentinels, which allow individuals to monitor different areas, became more frequent under windier conditions. Wind speed is not likely to affect manoeuvrability in sentinels that are already close to cover. Energy costs during high wind likely are not as relevant to sentinels as they may be to other group members, since sentinels do not forage. We conclude that the ability to assess risk visually was probably compromised by movements in the vegetation caused by wind. The study highlights behavioural adjustments to weather-related environmental variability.

Birds doi: 10.3390/birds7010022

Authors: Heather Williams Leslie Reed-Evans

Elevated perches allow songbirds to better transmit their songs and increase the visibility of territorial displays, but there is a cost: increased predation risk. To investigate how grassland birds evaluate these tradeoffs, we placed artificial perches in one of four meadows kept open by mowing in Williamstown, Massachusetts. We tracked meadow and perch usage by passerine birds using both a weekly census and monthly counts of fecal boli as a proxy for occupancy of the artificial perches. The same species were observed in the meadow with artificial perches and the meadows without such perches. Nevertheless, all of the artificial perches were used, some extensively. Much of the variation in perch use could be explained by perch height. Birds preferred taller perches, which are the most visible to predators, but also provide the largest advantages in terms of song propagation and visibility for better territory advertisement. Other advantages include increased visibility for foragers hunting insects, as well as possible earlier detection of predators. The increased predation risk of perching in the open on higher perches appears to be offset by the advantages gained by being seen, being heard, and having a better view of the surrounding area.

Birds doi: 10.3390/birds7010021

Authors: Indrikis A. Krams Ronalds Krams Colton B. Adams Todd M. Freeberg Tatjana Krama

Predation risk influences how animals approach predictable food sources where ambush predators may be present. In parids, chick-a-dee calls are used in a wide variety of contexts related to social cohesion and are well known as mobbing signals. Here, we examined whether they are also produced in the absence of visible predators in contexts in which predation risk may nevertheless be latent or uncertain. We tested whether chick-a-dee calls emitted by Willow Tits (Poecile montanus) during feeder approach exhibit acoustic and recruitment characteristics comparable to mobbing calls elicited by predator models. The study included repeated observations of 44 individuals across 11 flocks, enabling within-individual comparisons across habitat contexts. We analyzed call structure, calling duration, and recruitment latency in relation to habitat visibility and dominance status. Calls produced during the feeder approach showed overlapping structural features with mobbing calls and were associated with the recruitment of flock members, particularly in dense habitat. Mixed-effects models confirmed significant effects of habitat structure, predator presentation, and social rank on calling behavior and recruitment dynamics. These patterns are consistent with mobbing-like signaling under conditions of uncertain predation risk. Because predator presence and detection outcomes were not directly measured, our findings provide behavioral evidence compatible with proactive signaling rather than functional confirmation of predator probing.

Birds doi: 10.3390/birds7010020

Authors: Simona Tarricone Giuseppe La Gioia Maria Antonietta Colonna Nicolò De Vito Massimo Lacitignola Domenico Gerardi Gianpasquale Chiatante Domenico Campanile Mariarosaria Fortunato Marco Ragni

The Turtle Dove is a regular migratory species widely distributed in Italy, though the information on its abundance in each Italian region is modest; thus, action plans have been implemented to improve its conservation. This is a preliminary study meant to provide information on the distribution and abundance of the TD in Apulia. We analyzed data collected during 2019–2023 within the Farmland Bird Index (FBI) project, whose sampling design was intensified to achieve more homogeneous coverage of the region. The survey method was based on unlimited-distance point counts lasting 10 min. Counts were carried out between 15 May and 15 June of every year, beginning from dawn until 12:00 AM, with each station visited once. A total of 211 TD birds were recorded across 147-point counts. The MaxEnt analysis showed that olive orchards, needle-leaved woodlands, and evergreen broad-leaved woodlands had a positive effect on species occurrence, whereas winter precipitation had a negative effect. The total estimate of pairs fell within the range 47.14–66. The estimated density for TD in Apulia was 0.87–1.16 birds/km2, while that of pairs was 0.69–0.97/km2. By relating the estimated densities to the area suitable for the species’ presence, the abundance of TD was estimated at approximately 17,337–24,303 birds.

Birds doi: 10.3390/birds7010019

Authors: Belgica Porras-Reyes Juan Francisco Ornelas Carlos Lara

Behavioral flexibility allows animals to adjust their behavior in response to environmental changes. Hummingbirds, with their tetrachromatic color vision and enlarged hippocampal formation, represent an excellent model for studying cognitive flexibility in color discrimination. We evaluated three components of behavioral flexibility (exploration, exploitation, and inhibition) in two sympatric hummingbird species, the resident White-eared Hummingbird (Basilinna leucotis) and the migratory Broad-tailed Hummingbird (Selasphorus platycercus), using a reversal learning task with artificial flowers of different colors for evaluating exploration, exploitation, and inhibition simultaneously. Birds were trained to associate nectar rewards with either spectrally similar (red-yellow) or dissimilar (red-violet) color pairs. Our results revealed interspecific differences in exploration behavior depending on the rewarding color during training, while both species showed similar exploitation and inhibition capacities. The migratory S. platycercus showed stronger neophobia toward non-red flowers compared to the resident B. leucotis. Both species quickly learned the color-rewarding association when red was rewarding but required more visits when non-red colors were rewarding. These findings suggest that while both species can flexibly adjust their foraging behavior, differences in their ecology and migratory behavior may influence their initial responses to novel color cues.

Birds doi: 10.3390/birds7010018

Authors: Alexis Agtzidis Christos Barboutis Sinos Giokas

Avian morphology is a product of complex interactions among ecology, behavioral traits, and phylogeny. The wing, as a primary aerodynamic structure, is particularly indicative of these selective pressures, which are especially pronounced in migratory species. This study investigates interspecific variation in wing morphology among three migratory warblers of the family Sylviidae: the Garden Warbler (Sylvia borin), Eurasian Blackcap (Sylvia atricapilla), and Common Whitethroat (Curruca communis). We combined traditional morphometric measurements (body mass, wing length, primary feather lengths, and wing area) with functional aerodynamic indices (wing loading, aspect ratio, Kipp’s index) and geometric morphometric analysis of wing shape. Data were collected during autumn migration on the Greek island of Antikythera, a key stopover site in the Mediterranean. Our analysis revealed distinct morphological adaptations: Garden Warblers possessed elongated, pointed wings with a high aspect ratio, indicative of selection for long-distance, energy-efficient flight. Conversely, Eurasian Blackcaps exhibited shorter, rounder wings, a morphology associated with high maneuverability and quicker takeoffs in dense habitats. Common Whitethroat displayed an intermediate wing morphology, balancing aerodynamic efficiency with maneuverability. These findings possibly demonstrate how wing morphology reflects a compromise shaped by selective pressures, including migratory distance, habitat structure, foraging behavior and predation risk.

Birds doi: 10.3390/birds7010017

Authors: Andrea Gestoso María Vidal José A. de Souza Manuel Martínez-Lago Francisco Rosende Jesús Domínguez

Bird survival is influenced by both natural and anthropogenic factors, including weather conditions and oil spills. In this study, we examined the impact of a major oil spill (Prestige oil tanker) and climatic conditions (precipitation and wind) on survival and recapture probability in the Kentish plover (Anarhynchus alexandrinus) population in Galicia (NW Spain). To this end, we applied the Cormack–Jolly–Seber (CJS) live recapture model to a sample of 372 adult birds captured between 1994 and 2023. The best-fit model indicated that survival was best explained by the interaction between precipitation and the Prestige oil spill, indicating a decrease in survival post-spill, especially in the periods Post1 (years 2003–2007) and Post2 (2008–2015). Precipitation showed a negative influence on adult survival, but wind had no significant influence. Recapture probability was influenced by the interaction between time, sex, and Prestige, with males showing higher values, probably due to behavioural and detectability differences. Environmental monitoring and preparedness for pollution events are therefore essential to improve the long-term viability of the species.

Birds doi: 10.3390/birds7010016

Authors: Şerban Procheş Erwin J. J. Sieben

Birds are a popular group of organisms for researchers and laymen alike, and citizen science data are widely used in understanding bird ecology. This study investigates the correlates of bird visits to a single tree in the suburb of Westville, located in the city of Durban (eThekwini Municipality), in coastal subtropical South Africa. Of the 416 bird species recorded locally (within the quarter-degree square where the tree is located), 47 visited the tree during the 108 observation hours spread over one year. Of the 636 bird visits, most were very brief (shorter than one minute), with birds departing in a direction different from the one from which they came, suggesting that the tree was most often used as a stopover. Feeding (mostly on insects) was observed during 112 visits, while other behaviors were rare. Bird activity was higher in spring/summer and in the early morning, with a weak second peak in the late afternoon. Larger birds used larger branches as perches and paid longer visits. There was a negative relationship between bird activity and butterfly activity, driven by different seasonal patterns, and this creates an opportunity for butterfly watching at a time of the year with low bird activity. These results are used to discuss potential directions for similar projects while harnessing citizen science.

Birds doi: 10.3390/birds7010015

Authors: Jorge Luis Cortinas-Salazar Cristina García-De la Peña Quetzaly K. Siller-Rodríguez Sergio I. Barraza-Guerrero Verónica Ávila-Rodríguez Jesús Vásquez-Arroyo Juan Carlos Herrera-Salazar Luis M. Valenzuela-Núñez Juan Carlos Ontiveros-Chacón Annely Zamudio-López Judith Correa-Gómez Alexandra M. Arellano-Correa Dannia I. Orozco-López

The gut microbiota plays a key role in the health of wild birds, reflecting the influence of diet, habitat, and social behavior. Migratory and highly gregarious species such as the yellow-headed blackbird (Xanthocephalus xanthocephalus) provide valuable opportunities to explore host–microbe–environment interactions within a One Health framework. During migration, birds are exposed to diverse environments and dietary sources, which can promote highly diverse intestinal microbial communities and facilitate transient acquisition of environmental microorganisms. Here, we present the first taxonomic characterization of the fecal bacterial microbiota of X. xanthocephalus in northern Mexico based on 16S rRNA gene sequencing of the V3–V4 region. In addition, we performed a conservative screening to assess whether any bacterial taxa tentatively assigned at the species level have been previously reported as human pathogens or as having potential zoonotic relevance. Fecal samples were collected noninvasively from communal roosts within an urban–agricultural landscape of the Comarca Lagunera region during a winter season. A highly diverse bacterial community (39 phyla, 369 families, and 1195 bacterial species) was identified. Firmicutes_D, Actinobacteriota, and Campylobacterota were the dominant phyla. Among the bacterial taxa tentatively assigned at the species level, only three have been reported to exhibit zoonotic potential in the literature; however, none corresponded to avian-adapted pathogens or bacterial species historically associated with major zoonotic outbreaks, and all were detected at very low relative abundances. Overall, our findings establish an initial microbiological baseline for X. xanthocephalus and underscore the role of migratory birds as indicators of environmental microbial dynamics rather than direct sources of zoonotic risk in semiarid regions of northern Mexico.

Birds doi: 10.3390/birds7010014

Authors: Baiheng An Yun Yang Migmar Wangdwei

The combined effects of plateau pikas and yak grazing on the distribution or occupancy of endemic passeridae birds on the Qinghai-Tibetan plateau, China remain largely unknown. To assess habitat selection patterns within the frameworks of niche construction theory and the rivet hypothesis, we measured the occupancy rates of passeridae species along five sample strips of transects established in a treeless ecosystem. Each transect was surveyed three times within each seasonal sampling window (spring, summer, and autumn 2024), and repeated visits were treated as detection occasions for occupancy modeling. We used plateau pika density and yak grazing patterns as key variables to investigate their influence on the occupancy of alpine passeridae birds. We found that the occupancy of both the White-rumped and Rufous-necked Snowfinch was positively associated with proximity to yak bedding sites and high densities of plateau pika burrows. However, the occupancy of both species declined with increasing distance from yak bedding areas. In contrast, the Ground Tit showed no detectable association with these variables. This strong interspecific variation underscores the importance of disentangling mechanistic linkages among large herbivores, ecosystem engineers, and avian niche specialization in this fragile biome. Further research should explore how cross-taxa interactions mediate habitat availability and species resilience under ongoing environmental change.

Birds doi: 10.3390/birds7010013

Authors: Selmane Chabani Ghollame Ellah Yacine Khames Imad Djemadi Khalil Draidi Imad Eddine Rezouani Badreddine Mezhoud Abdenour Moussouni Kamel Eddine Mederbal Salah Telailia Badis Bakhouche

Ground-nesting shorebirds face growing pressure from recreational activities in coastal urban areas. We monitored the breeding success of Kentish Plover (Charadrius alexandrinus) and Little Ringed Plover (Charadrius dubius) over six consecutive years (2020–2025) at the Promenade of Sablettes, a heavily visited waterfront in Algiers, Algeria. We combined field surveys with multi-sensor remote sensing analysis using Sentinel-1, Sentinel-2, and Dynamic World data to quantify habitat change. A total of 105 nests were recorded across both species. Breeding success reached 70% during the COVID-19 lockdown period (2020–2021), when human visitation dropped sharply. In contrast, complete reproductive failure occurred in 2022 and 2023, coinciding with resumed tourism and unplanned construction activities. Remote sensing revealed that 80–85% of the study area experienced severe habitat degradation between 2020 and 2025, while suitable refuge zones shrank to less than 10% of the total surface. Fledged chicks consistently moved toward a less disturbed vegetated zone, highlighting its functional importance for brood survival. Our results show that human disturbance is the primary factor limiting breeding success at this site, operating through two pathways: direct disturbance of nesting birds and progressive habitat degradation driven by recreational use and unplanned construction. When disturbance was reduced during the pandemic, the habitat proved fully functional for both species. These findings suggest that simple management measures such as seasonal access restrictions and symbolic fencing during the April–July breeding period could restore breeding conditions without major habitat engineering. This study provides one of the first integrations of long-term field breeding data with landscape-scale remote sensing to document the effects of the anthropause and subsequent recovery on urban shorebird populations.

Birds doi: 10.3390/birds7010012

Authors: Virginia Morandini Jorge García-Macía Miguel Ferrer

The post-fledging dependence period is a crucial stage in the development of altricial birds that may influence their future performance and fitness. This period is regulated by parental investment, in terms of food provisioning and protection, and the young’s demands associated with their development and physical condition. We examined post-fledging dependence regulation in 21 Booted Eagle (Hieraaetus pennatus) nestlings in southern Spain. We compared the dependence timing among juvenile birds from different territories. Here, we analyzed the blood plasma chemistry of nestlings in southern Spain and compared blood biochemistry parameters, including urea levels and a body condition index with the hatching date. Urea levels showed a stronger negative relationship with the length of dependence period than with the hatching date or body condition index. Our results support that better nourished nestlings attain independence later than those in an inferior condition, highlighting the potential of urea levels as a reliable indicator of nestling status. In this study, we describe the concentrations of selected chemical parameters in the plasma of free-living Booted Eagle nestlings, including chemical parameters that have been shown to be related to nutritional condition. Young with a better nutritional condition started dispersal later. Blood parameters can be used as a very useful complementary technique when approaching ecological issues. Early dispersal onset seems to be controlled by endogenous factors that are evolutionarily selected since it should provide inherent benefits in terms of future fitness.

Birds doi: 10.3390/birds7010011

Authors: Hector Leal-Aguayo Blanca Catalina Ramírez-Hernández José L. Navarrete-Heredia Flor Rodríguez-Gómez Paulina Beatriz Gutiérrez-Martínez Marcela Mariel Maldonado-Villegas Diana Vega-Montes de Oca Diego A. García-Núñez Aura Libertad Calleja-Rivera

This study evaluated heavy metal accumulation in bird feathers across four contrasting environments in Jalisco, Mexico (urban, semi-urban, agricultural, and semi-natural). We analyzed 370 feather samples from 58 species spanning seven trophic guilds using XRF spectrometry. Fifteen metals were quantified, with zinc (Zn) showing the highest concentrations overall. Multivariate analyses identified trophic guild as the strongest predictor of metal variation, while spatial differences were present but less pronounced. CUAltos was the only site consistently distinct from the others, mainly due to lower concentrations of several metals. Despite quantitative differences among guilds, their proportional metal profiles were similar—dominated by Zn, Y, Mo, and Hf—suggesting broad regional exposure rather than guild-specific accumulation. Redundancy Analysis indicated that atmospheric pollutants (COV and PM10) were the main environmental drivers of spatial variation, especially in Guadalajara’s urban sites. Agricultural variables, including agave cover, showed minor and non-significant effects. Neither sex nor migratory status influenced metal loads, consistent with feathers reflecting exposure during feather growth at the molt site, while potentially also incorporating locally deposited external contaminants. Overall, this study demonstrates the effectiveness of feathers as a non-invasive biomonitoring tool and highlights air quality as a key determinant of regional heavy metal contamination.

Birds doi: 10.3390/birds7010010

Authors: Sarah L. Foltz

Many cemeteries include large amounts of greenspace and so have substantial potential to support urban plant and wildlife communities. However, the physical structure and design of these human-focused greenspaces may ultimately determine which species successfully inhabit these areas. Here, I studied the relationship between grave markers, a unique and ubiquitous feature of cemeteries that vary widely in shape and structure within and between burial areas, and the behavior of cemetery avian communities. I hypothesized that areas with greater structural heterogeneity of markers would be used by a larger diversity of species and that species would alter their behavior and interactions with markers based on marker structure. I assessed avian abundance and species richness in areas with varied upright and homogenously flat grave markers and observed behaviors exhibited by four common species in relation to grave markers and other structural features. While I found no relationship between grave marker heterogeneity and avian species richness or abundance, there is evidence for species-specific behavior and interactions with grave markers, suggesting that marker design is an important and relevant landscape feature for birds. These results have practical applications for cemetery design at a time when there is both increased public interest in environmentally friendly burials and growing competition for land in increasingly heavily developed urban areas.

Birds doi: 10.3390/birds7010009

Authors: Jaemy Romero-Herrada Eduardo Nycander Bruno Díaz César Arana Letty Salinas

Cavity limitations and interspecific competition render large macaws valuable models for elucidating the integration of parental care, pair-bond maintenance, and nest defense across reproductive stages. Through continuous video monitoring of a single artificial polyvinyl chloride nest box in the Tambopata National Reserve, Peru, we quantified the complete breeding cycle of a resident green-winged macaw (Ara chloropterus) pair and the visitation behavior of a sympatric scarlet macaw (Ara macao) pair within the same cavity. We constructed daily time budgets for 17 behaviors, categorized into seven functional groups, from motion-triggered video clips; employed multivariate tests; and generalized additive models with beta error distribution to describe the temporal changes across the five reproductive stages. The resident A. chloropterus exhibited a significant reorganization of parental investment, with early courtship behaviors transitioning to peak nest attendance and sentinel vigilance during incubation and early brooding. In later stages, locomotion increased significantly, associated with chick provisioning, whereas the frequency of allopreening remained relatively constant throughout the cycle. The visiting A. macao displayed a brief, behaviorally rich prospecting phase, characterized by nest inspection and locomotion, followed by a sharp decline in minimal activity. These divergent strategies align with owner–intruder asymmetries and floater dynamics, indicating that artificial cavities can support A. chloropterus breeding, while suggesting that additional cavities may redistribute breeding opportunities among competing macaws, a hypothesis necessitating multi-nest and multi-year evaluation.

Birds doi: 10.3390/birds7010008

Authors: Włodzimierz Meissner Marta Witkowska Pavel Pinchuk Natalia Karlionova

The possibility of sex identification in birds is of substantial importance for studies on various aspects of their ecology and behaviour. Discriminant functions have become increasingly popular in studies of bird species that are monomorphic in plumage characteristics because these methods are inexpensive and non-invasive. In this paper, we provide the first discriminant function that could potentially aid in determining sex in a common wader species, the Wood Sandpiper, based on external body measurements. Females were larger than males in all linear body measurements; however, no single measurement can be used to determine sex due to the high degree of overlap between the sexes. Discriminant equation with the most commonly used linear measurements, wing length and bill length, was provided. Identifying birds with discriminant function values D3 < –0.409 as males and those with D3 > 0.217 as females would lead to sex misclassification of only 5% of individuals of each sex, but it would leave as many as 83% of the individuals unsexed. Allowing for a misclassification of 10% would shift the cut-off values to −0.509 for males and 0.633 for females and reduce the number of unsexed birds to 66%. The method presented here allows us to account for sex-specific patterns in future ecological studies of the Wood Sandpiper and can be applied to past data.

Birds doi: 10.3390/birds7010007

Authors: Roshan Tailor Toni Gordon Raquel Gil Carrasco Gabriela Vigo-Trauco Donald J. Brightsmith

Illegal wildlife trade exerts severe pressure on wild parrot populations, and confiscated parrots often end up in rescue centers where they are rehabilitated for release. However, parrots kept in captivity often develop potentially maladaptive behaviors, including attraction to humans. This behavior can increase the risk of recapture. We modified and tested a previously published human aversion training (HAT) protocol designed to reduce human attraction in confiscated Amazona parrots. The HAT consisted of observers either on the ground or on a ladder, offering food to a single individual and then feigning capture of birds that approached or failed to move away from the observer. Twelve Yellow-naped Amazons (Amazona auropalliata) underwent 36 sessions of HAT over a 14-week period. Ten additional birds were held without training as a control. All birds were evaluated through food offer tests (FOTs) before, during, and after the experiment (FOT scores ranged from 1 when the bird approached the observer to 6 when the bird flew away). Over the training period, both groups showed increased aversion to people. However, contrary to our predictions, aversion scores were not higher for the group given aversion training. Aversion training also did not have a strong impact on fate post-release: within a month of release, 40% of the 22 birds were recaptured in a nearby village, including 4 treatment and 5 control birds. Overall, these results suggest that holding these birds in monospecific groups increased aversion to humans. However, the intense training aversion protocol did not further increase the fear of humans in these Amazona parrots, many of which may have been pets for years before entering the program. This study suggests that rehabilitation and release projects should regularly evaluate the impacts of their training programs and improve or eliminate costly protocols that do not achieve stated objectives.

Birds doi: 10.3390/birds7010006

Authors: Constantin Ion Vasile Jitariu Lucian Eugen Bolboacă Pavel Ichim Mihai Marinov Vasile Alexe Alexandru Doroșencu

Climate change and altered hydrological regimes are restructuring wetland habitats globally, triggering cascading effects on colonial waterbirds. This study investigates how environmental drivers, including thermal anomalies, water-level fluctuations, and aqueous surface extent, influence the distribution and size of waterbird colonies (Ardeidae, Threskiornithidae, and Phalacrocoracidae) in the Danube Delta Biosphere Reserve. We integrated colony census data (2016–2023) with remote-sensing-derived habitat metrics, in situ meteorological and hydrological measurements to model colony abundance dynamics. Our results indicate that elevated early spring temperatures and water level variability are the primary determinants of numerical population dynamics. Spatial analysis revealed a heterogeneous response to hydrological stress: while the westernmost colony exhibited high site fidelity due to its proximity to persistent aquatic surfaces, the central colonies suffered severe declines or local extirpation during extreme drought periods (2020–2022). A discernible eastward shift in bird assemblages was observed toward zones with superior hydrological connectivity and proximity to anthropogenic hubs, suggesting an adaptive spatial response that was consistent with behavioral flexibility. We propose an adaptive management framework prioritizing sustainable solutions for maintaining minimum lacustrine water levels to preserve critical foraging zones. This integrative framework highlights the pivotal role of remote sensing in transitioning from reactive monitoring to predictive conservation of deltaic ecosystems.

Birds doi: 10.3390/birds7010005

Authors: C. T. Shifa Jenny A. Angarita-Báez K. A. Rubeena Thayyullathil Jobiraj Punathil Thejass Sabir Bin Muzaffar Mudasir Nayeem Mir T. R. Athira K. M. Aarif

Sympatric species are closely related taxa that coexist within the same habitat through niche partitioning, and kingfishers serve as an ideal group for studying such ecological mechanisms. The present study examined the perch height in relation to foraging behaviour and hunting success of five kingfisher species: Common Kingfisher (Alcedo atthis), White-throated Kingfisher (Halcyon smyrnensis), Pied Kingfisher (Ceryle rudis), Stork-billed Kingfisher (Pelargopsis capensis), and Black-capped Kingfisher (Halcyon pileata). The study was conducted between 2021 and 2023, across seven habitat types in Kerala, India (Kadalundi–Vallikkunnu Community Reserve (KVCR) mangroves, Kallampara mangroves, Vadakkumpad mangroves, Vazhakkad agroecosystem, Mavoor wetland, Sanketham wetland, and Elathur beach). A generalized linear mixed model (GLMM) with a binomial distribution and logit link function was used to analyze hunting success across species. The model indicated that the effect of perch height on hunting success varied among species, though neither perch height nor species identity alone had a significant effect. Most species favored mid-height perches (2–5 m) for foraging, with the Common Kingfisher exhibiting moderate success across all heights and habitats. The Pied Kingfisher showed significantly reduced success at higher perches, while the Stork-billed Kingfisher achieved the highest success at mid-heights (2–5 m). The White-throated Kingfisher showed a non-significant negative association with capture success, whereas the Black-capped Kingfisher exhibited a neutral to positive relationship across perch heights. Among all variables tested, prey availability emerged as the sole significant predictor of hunting success, indicating that prey abundance is the principal determinant of foraging efficiency in tropical wetlands, rather than environmental conditions. Our findings confirm a pattern of vertical stratification in resource partitioning among sympatric kingfisher species and underscore the importance of conserving habitats that retain natural perch sites of varying heights.

Birds doi: 10.3390/birds7010004

Authors: Anita Studer Leïla Perroulaz

Information on the breeding of the Pinto’s Spinetail (Synallaxis infuscata), an endangered Brazilian Furnariid, is scarce. This study aims to complement it, by looking at nest and clutch parameters, breeding period, and nest success. Once nests were found, they were closely monitored from a hide. Between 1986 and 2018, 33 nests were found in the Pedra Talhada Forest near Quebrangulo. Nests were found year-round, except in middle of the dry season. Nests were of the closed/retort type, weighing 552.1 g, and measuring 37.6 × 28.8 cm, with a side arm of 30.6 × 4.9 cm, on average. The clutch size averaged 2.10 eggs, which measured 22.3 × 17.2 mm and weighed 3.2 g. They were white and had an oval to pointed-oval shape. Mean incubation period was 21.5 days and mean nestling period 14.71 days. The apparent nest success was 27.3%, while Mayfield’s was 21.8%. Predation was the main cause of nest failure, accounting for 81% of cases. The breeding data we collected on S. infuscata falls within the range of observations of a comprehensive analysis on other Synallaxis species. This breeding information is important for conservation, as rates of nest loss are a key factor in evaluating population viability.

Birds doi: 10.3390/birds7010003

Authors: Karolina Cieślińska Romana Cieślińska Brygida Manikowska-Ślepowrońska

Rapid global urbanization has led to the loss and degradation of many natural habitats, causing numerous bird species to inhabit and breed in cities. Here we investigated the influence of multiple factors on the number of chicks of the four common waterbird species, from Anatidae [Mallard (Anas platyrhynchos), Mute Swan (Cygnus olor)] and from Rallidae [Eurasian Coot (Fulica atra), Common Moorhen (Gallinula chloropus)], nesting in Gdańsk (Poland) in 2020 and 2021. We found that the harsh winter before the 2021 season may have resulted in a lower number of chicks in rallids. Rainfall and higher temperatures during breeding season increased the number of rallids’ chicks. Larger waterbodies were associated with a lower number of chicks (except for Moorhen). However, a longer shoreline was related to a higher number of chicks of all species. The Normalized Difference Moisture Index, indicating absence of urban fabric, positively impacted the number of chicks of all species, except for Mallard. The distance of waterbody from areas with varying degrees of urbanization had a diverse effect on the number of chicks of each species, except for Swan. Our results emphasize the importance of urban reservoirs for breeding birds and highlight the need to preserve natural features, such as allowing bank vegetation and reeds to grow, to provide nesting sites and shelter.

Birds doi: 10.3390/birds7010002

Authors: Valeria López-Hernández Leopoldo D. Vázquez-Reyes Ana María Contreras-González Victor H. Jiménez-Arcos Jorge Tanit Rodríguez-Malacara Megan P. Trejo-Boyso Taisha Lara-Moreno Jose Alfredo Rodriguez Cesar Mateo Flores-Ortiz Francisco Alberto Rivera-Ortiz

The Military Macaw is a Neotropical psittacid that is endangered in Mexico. It faces significant threats due to habitat loss and the illegal pet trade. However, little is known about the nutritional characteristics of the plant resources available to this species throughout its annual cycle. This study aimed to characterize the nutritional profile of the fruits consumed by macaws in the Alto Balsas Basin, Mexico, and to infer potential seasonal patterns in the availability of the fruits they feed on in relation to the Macaws’ reproductive phenology. We identified 13 plant species that have been consistently reported as components of the diet of the macaws within the Alto Balsas Basin using a literature review, field observations, and local interviews. We conducted bromatological analyses to assess the content of moisture, protein, lipids, carbohydrates, and fiber for the pulp and seeds of all 13 identified plant species. Although we did not measure quantitative food intake, we integrated these data with reproductive phenology and resource availability to infer potential patterns of nutritional use. The results revealed significant differences in nutritional content among the different species, as well as seasonal variation in the nutritional profiles of available resources that coincide with the physiological demands of the macaw life cycle. During the non-breeding season, the availability of species whose fruits have high lipid and carbohydrate contents, such as Bursera spp., hackberry and madras thorn, may provide essential energy. Conversely, during the breeding season, resources with higher lipid and protein content (such as Mexican kapok tree and red mombin) could support the increased energetic investment associated with courtship, egg production, and chick provisioning. Although our study did not directly quantify the amount of each food item consumed, the integration of nutritional and ecological data provides a preliminary view of how resource quality may influence seasonal foraging patterns, offering valuable insights for the conservation and management of this species.

Birds doi: 10.3390/birds7010001

Authors: Adiv Gal Malamati A. Papakosta Christos G. Vlachos Dimitrios D. Bakaloudis Vassilis Goutner Reuven Yosef

Intraspecific brood parasitism (IBP), where one female lays eggs in another’s nest, is considered rare in raptors, including typically monogamous and solitary or semi-colonial falcons. The Lesser Kestrel (Falco naumanni) is a colonial falcon with a usual clutch size of one to five eggs, yet two independent cases of anomalously large clutches consistent with suspected IBP are described from long-term studies in Greece and Israel. In central Greece (Armenio; 39°29′ N, 22°41′ E), a nest box colony monitored since 1998 produced a clutch of eight unhatched eggs in 2017; egg volumes formed two statistically distinct groups (V1 = 850.74 ± 27.72 vs. V2 = 926.78 ± 18.87 mm3; t = 4.146, p = 0.006), suggestive of contributions from two females. In Israel (Alona District; 32°35′ N, 35°05′ E), a nest under an asbestos roof contained a mixed clutch of eight eggs laid over two seasons (2003–2004), with four new eggs added to four unhatched eggs from the previous year; only one egg hatched and the chick was subsequently predated by a Little Owl (Athene noctua). Given the species’ typical clutch size and the occurrence of double clutches, these cases are interpreted as rare instances of parasitic egg-laying. Their extreme rarity—only one event over more than 20 years of monitoring ~120 pairs annually in Greece—underscores how uncommon IBP appears to be in Lesser Kestrels and how easily such events may be overlooked without intensive, long-term monitoring. The results emphasize the need to combine detailed field observations with molecular parentage analyses, quantify IBP frequency, and clarify the ecological and evolutionary relevance of alternative reproductive strategies in this and other colonial raptors.

Birds doi: 10.3390/birds6040066

Authors: Jennifer L. Reidy

Incomplete detection during auditory point counts includes the component that individuals are present but silent (“availability”). If the probability of being ‘available’ is less than one and is not random with respect to time or space, population estimates that fail to address availability will be biased. I recorded minute-by-minute singing of 60 male Golden-cheeked Warblers (Setophaga chrysoparia) in 2010–2011 (133 surveys; 6517 min) to estimate availability, evaluate predictors, and provide survey guidance. The per-minute availability was 0.45 (95% confidence intervals [CI]: 0.37–0.54). The availability was higher for unpaired versus paired males (0.82 [0.64–0.92] versus 0.30 [0.20–0.42]) and when ≥1 conspecific was singing (0.61 [0.46–0.75] vs. 0.54 [0.39–0.68]). Availability declined across both day of year and hour of day. Aggregating to common survey lengths, the probability of ≥ 1 song per bin increased with duration but showed the same temporal declines: 3 min = 0.61 (0.52–0.70), 5 min = 0.72 (0.63–0.79), and 10 min = 0.83 (0.74–0.90). Temperature had a modest positive effect, clearest at the 10 min bins. Interaction terms among day, hour, and temperature were unsupported (all likelihood ratio tests p > 0.10). These findings indicate that availability is <1 and varies predictably with day and time, implying that point count protocols should standardize survey windows or model availability explicitly.

Birds doi: 10.3390/birds6040065

Authors: Jukka Jokimäki

Birds was founded on September 2020 [...]

Birds doi: 10.3390/birds6040064

Authors: Momoyo Fujioka Maki Yamamoto Masaki Shirai

Corvids exhibit avoidance behaviour when foraging in the presence of potentially risky stimuli, yet it remains unclear how stimulus characteristics influence the strength of such responses. In this paper, we present wild-caught Large-billed Crows (Corvus macrorhynchos) with five conditions: no visual stimulus, a cardboard box (non-biological, stationary), an immobile owl decoy (biological, stationary), a continuous-motion owl decoy (biological, moving), and a sensor-activated-motion owl decoy (biological, moving, and sudden). Avoidance was quantified using feeding latency, landing frequency, total time spent in the feeding area, and food consumption. Compared with the condition with no visual stimulus, the presence of any visual stimulus elicited increased latency, indicating that crows detect and respond to objects near food. Among the four objects, the sensor-activated-motion owl decoy produced stronger avoidance responses of the crows than the non-biological and stationary object (cardboard box). This indicates that they evaluate not only the presence of an object but also its motion characteristics and/or perceived biological cues when adjusting their foraging behaviour. Although sample size and individual variation impose limitations, these findings suggest that both the presence of visual stimuli and/or the complexity of their appearance play key roles in shaping avoidance behaviour in corvids.

Birds doi: 10.3390/birds6040063

Authors: Dajana Davitkov Tamara Ilic Milan Vidakovic Sofija Solaja Vladimir Nesic Nemanja M. Jovanovic

Parasitic infections represent an important health challenge in falcons (Falconidae), where they may negatively influence survival, reproduction, and performance. This study is the first investigation in Serbia assessing the prevalence and diversity of endoparasites in captive falcons, with special emphasis on Serratospiculum spp. A total of 145 live birds (hybrid falcon, Falco peregrinus, F. cherrug, F. rusticolus) and 1 dead individual were examined. Diagnostic procedures included necropsy, coprological analysis, and molecular detection. Endoparasites were confirmed in 55.2% of fecal samples. The most frequent were Caryospora spp. (41.4%), followed by Porrocaecum spp. (18.6%), Capillaria spp. (3.4%), and Serratospiculum spp. (2.8%). Statistically significant differences were observed between sexes, locations, and preventive health management. Falcons kept under preventive measures showed a markedly lower prevalence compared with those lacking such care. These findings highlight the persistent occurrence of endoparasites in Serbian falcons and underscore the importance of preventive programs. Regular deworming, strict hygiene, and vector control represent essential strategies for minimizing infections, particularly of Serratospiculum spp., which poses a serious respiratory health threat.

Birds doi: 10.3390/birds6040062

Authors: Remo Probst Renate Probst

Raptors wintering in temperate regions face strong energetic constraints due to low temperatures and limited prey availability. Understanding how intrinsic traits and environmental conditions shape hunting performance helps to clarify the mechanisms underlying winter foraging efficiency. We studied wintering Hen Harriers (Circus cyaneus) in Austria over five consecutive winters (2020/21–2024/25) to quantify touchdown attempt rate and outcome in relation to sex, age, territorial status, and weather. Using generalized linear mixed models, we analyzed 1829 recorded touchdowns with individual identity as a random effect. Territorial females showed slightly higher attempt rates than males, whereas non-territorial females exhibited a tendency toward lower touchdown success. Adult males achieved the highest per-attempt efficiency, but age alone had no significant effect. Touchdown outcomes improved under cloud cover and declined with wind speed, while temperature showed no influence. Attempt rate was unaffected by any environmental variable. These results demonstrate that both intrinsic and extrinsic factors jointly determine winter foraging performance: males, with their smaller body size and agility, can persist even in vole-poor habitats by compensating through efficient flight and prey capture; territorial females benefit from stable access to vole-rich patches; and non-territorial females remain constrained by competition and limited access to prey. The findings highlight the need to maintain open farmland and vole-rich habitat to support diverse overwintering strategies.

Birds doi: 10.3390/birds6040061

Authors: Seon-Ju Lee Bo-Yeon Hwang Jongmin Yoon

Nest defense is a key component of avian reproductive success, yet its intensity and expression often depend on ecological and social contexts. We investigated the nest defense behaviors of Saunders’s Gulls (Saundersilarus saundersi) breeding in Incheon Bay of South Korea in 2022 in relation to nest density and perceived threats. Using decoy presentations of three heterospecifics, Oriental Magpie (Pica serica; diurnal avian nest predator), common raccoon dog (Nyctereutes procyonoides; nocturnal mammalian nest predator), and Little Tern (Sternula albifrons; neutral co-nester), we quantified latency to respond, bombing attack rate, and the number of mobbing individuals at high- and low-density nesting sites within a breeding colony. Mixed models revealed that latency to respond and attack rates varied strongly with stimulus type, with diurnal predator magpies eliciting the fastest and most intense responses, followed by nocturnal predator raccoon dogs and co-nester terns. Nest density influenced the number of mobbing individuals, which was significantly greater at high-density sites. Principal Component Analysis reduced the three behavioral metrics into a composite score, which correlated negatively with latency and positively with bombing attack rate and mobbing intensity. This score varied with both nest density and stimulus type. Our findings demonstrate that Saunders’s Gulls adjust their nest defense strategies according to both the social context and predator type, highlighting the importance of density-dependent collective nest defense in colonial breeders.

Birds doi: 10.3390/birds6040060

Authors: Leroy J. Walston Jules F. Cacho Ricardo A. Lesmes-Vesga Hardev Sandhu Colleen R. Zumpf Bradford Kasberg Jeremy Feinstein Maria Cristina Negri

Birds are important indicators of ecosystem health and provide a range of benefits to society. It is important, therefore, to understand the impacts of agricultural land use changes on bird populations. The cultivation of energycane (EC)—a sugarcane hybrid—for biofuel production represents one form of agricultural land use change in southern Florida. We used passive acoustic monitoring (PAM) to examine bird community use of experimental EC fields and other agricultural land uses at two study sites in southern Florida. We deployed 16 acoustic recorders in different study plots and used the automatic species identifier BirdNET to identify 40 focal bird species. We found seasonal differences in daily avian species diversity and richness between EC experimental plots and reference agricultural fields (corn fields, orchards, pastureland), and between time periods (pre-planting, post-planting). Daily avian species diversity and richness were lower in the EC experimental plots during Fall and Winter months when plants reached maximum height (>400 cm in some areas). Despite seasonal differences in daily measures of species diversity and richness, we found no differences in cumulative species richness, suggesting that there may be little overall (season-long) effects of EC production. These findings could provide insight to avian seasonal habitat preferences and underscore the potential limitations of PAM in areas experiencing dynamic vegetation changes. More research is needed to better understand if utilization of EC cropping systems results in positive or negative effects on avian populations (e.g., foraging habitat quality, predator–prey dynamics, nest success).

Birds doi: 10.3390/birds6040059

Authors: Monica Guerrini Hans-Martin Berg Sylke Frahnert Manuel Biscoito Filippo Barbanera

The Red-legged Partridge (Alectoris rufa, Phasianidae) is a non-migrant gamebird endemic to southwestern Europe that was introduced into Mediterranean and Atlantic islands in historical times. This is the case for Madeira, Portugal, where a population morphologically assigned to A. r. hispanica has been present since the XV century. We assessed its genetic identity using 2248 (Cytochrome-b, Cyt-b + Control Region, CR) and 297 bp-long (CR) mitochondrial DNA sequences obtained from modern and archival (1900–1964, including Caccabis rufa maderensis syntypes) partridges, respectively. These sequences were compared against an already published dataset covering the entire Iberian A. rufa range. We found that all the haplotypes of modern birds from Madeira were private to this island. The putative subspecies was confirmed, and northern Portugal with northwestern Spain turned out to host the closest mainland populations. This result was in line with the origin of the first human settlers of Madeira from, among other historical provinces, Douro Litoral and Minho, the latter neighboring Galicia. Despite relatively recent A. rufa importations from continental Europe, we did not find any significant change over time in the haplotypic pattern of Madeiran partridges as well as any evidence for maternal introgression from species such as the congeneric Chukar Partridge (A. chukar). Studies relying on genome-wide markers and including the only captive-bred population of Madeira are needed to gain more comprehensive information for the management of the local A. rufa.

Birds doi: 10.3390/birds6040058

Authors: Mohan Ram Devesh Gadhavi Aradhana Sahu Nityanand Srivastava Tahir Ali Rather Tanisha Dagur Vidhi Modi Lahar Jhala Yashpal Zala Dushyantsinh Jhala

Reintroduction efforts of wildlife species seek to re-establish self-sustaining populations of targeted species within their historical ranges. Our study focuses on the Indian Grey Hornbill, which faced local extinction in the Gir National Park and Sanctuary, Gujarat, India. The last recorded direct sighting of the Indian Grey Hornbill in the study area dates back to the 1930s. Its presence gradually declined, leading to its eventual extinction in the region between 1950 and 1960. Since the declaration of Gir Forest as a sanctuary in 1965 and subsequently as a national park in 1975, habitat conditions have significantly improved. This positive trend created an opportunity for the reintroduction of the hornbills to establish a self-sustaining population. The reintroduction was conducted in two phases. During the first phase, twenty-eight birds were captured from known hornbill ranges within Gujarat, and five of them were equipped with PTT/GSM satellite transmitters. And in the second phase, twelve birds were captured, and six of them were fitted with PTTs to study their ranging patterns, habitat associations, and potential breeding activities. During the establishment or initial phase of reintroduction, the birds exhibited exploratory behaviour, resulting in larger home ranges (mean ± Standard Deviation, SD) (60.87 ± 68.51 km2), which gradually reduced to smaller home ranges (5.73 ± 10.50 km2) during later stages. Similarly, the daily and monthly distances travelled by the birds were significantly greater in the initial phase than in the later one. Nest site selection correlated significantly with girth at breast height (GBH) and tall trees. Our study provides essential information for hornbill reintroduction in the Gir landscape, aiding future conservation efforts for Indian Grey Hornbills.

Birds doi: 10.3390/birds6040057

Authors: Christoph Randler Florian Dechant

AI tools like Passive Acoustic Monitoring (PAM) and apps like iNaturalist and Merlin are increasingly used in bird monitoring and species identification. The purpose of this study was to assess whether AI-assisted binoculars improve bird species knowledge, particularly in novice birders, and to examine users’ motivation and experience. This study focuses on the learning impact of users, not data quality or accuracy of the device itself. Participants were recruited via social media, mostly novices (10 women, 9 men, 1 diverse). Four experimental groups (A–D, with N = 5 participants each) were designated. Participants used AI-supported binoculars to identify 10 bird species and the same binoculars with AI function switched off to identify another 10 bird species based on two sets of different species (counterbalanced to avoid order effects). This allowed a between-group as well as a within-subject comparison. We used a pre-test/post-test design for learning. Significant knowledge gains occurred only when using AI binoculars (Wilcoxon tests, p = 0.008). Pooled data across the intervention groups showed strong learning effects for AI-assisted users (Z = −3.736, p = 0.001). No significant learning occurred under control conditions. As a conclusion, AI-assisted binoculars significantly enhance bird identification learning in novices, but as a cautionary note, the study needs to be extended to live birds and in longitudinal settings.

Birds doi: 10.3390/birds6040056

Authors: Gary L. Ivey Andrew J. Caven Dorn M. Moore Sara K. Gomez-Maier

The Central Valley of California provides critical wintering habitat for Sandhill Cranes (Antigone canadensis), which rely on wetlands, grasslands, and grain crops to meet their energetic needs. However, temporary row crops that support Sandhill Cranes and other wintering birds are ostensibly being replaced by permanent woody crops, which offer little value for wetland and grassland-dependent species. To better understand how landcover changes may be affecting habitat availability for these wintering cranes, we analyzed landcover trends within priority crane wintering areas from 2008 to 2023. We employed a mixed-methods approach that allowed us to describe both linear and non-linear trends over time and across regions. Our findings indicate a significant decrease in landcover types suitable as crane habitat over the 16-year period (τ = −0.90, p < 0.001), with an average annual decline of approximately −1.15 ± 0.21% (B± 95% CI). The best-fit trendline showed that habitat suitability in priority wintering areas decreased from over 81% in 2008 to under 65% in 2023. Specifically, grasslands, rice fields, and alfalfa acreage declined across priority wintering areas, while woody landcover—including orchards, vineyards, and riparian forest breaks—increased significantly (τ = 0.88, p < 0.001; B = 1.14 ± 0.20%). These landscape-level changes may constrain the regional carrying capacity for Sandhill Cranes and reduce their overall resilience.

Birds doi: 10.3390/birds6040055

Authors: Miriam Soledad Vazquez Alberto L. Scorolli Sergio M. Zalba

Urbanization reshapes bird communities by filtering species according to their ecological traits, often reducing richness, altering relative abundances, and favoring a subset of functionally tolerant species that dominate urban assemblages. Some native taxa are able to inhabit cities, even using them as stepping stones for range expansion. We examined urban habitat use, microhabitat selection, and potential niche partitioning between two range-expanding thrushes (Austral Thrush [Turdus falcklandii] and Rufous-bellied Thrush [Turdus rufiventris]) in two urban settlements in the Pampas region, Argentina. Using 131 transects across green areas and urbanized zones, we related abundance patterns to habitat features at the transect scale and evaluated microhabitat selection at the individual level. Austral Thrush abundance increased with herbaceous cover, tree cover, and even concrete surfaces, suggesting a relatively high tolerance to fragmented green spaces within dense urban matrices. In contrast, Rufous-bellied Thrush showed a positive association with tree cover, avoided tall buildings, and reached higher abundance in the smaller city, consistent with its recent arrival in the region and preference for less intensively urbanized environments. Microhabitat data revealed marked vertical stratification: Austral Thrush foraged almost exclusively at ground level on grassy or bare substrates, while Rufous-bellied Thrush used trees, shrubs, and vines more frequently. These differences reflect fine-scale resource partitioning that may contribute to reducing niche overlap and favor the coexistence of both species in recently colonized urban areas, while recognizing that such dynamics occur within broader bird assemblages where multiple species interact and compete for space and resources. Our findings highlight that even closely related species can respond divergently to urban structure, and that maintaining structural and substrate heterogeneity within cities may help support native bird diversity.

Birds doi: 10.3390/birds6040054

Authors: Alan Omar Bermúdez-Cavero Edgar Bernat-Ponce José Antonio Gil-Delgado Andrés López-Peinado

The Red Kite (Milvus milvus), a Western Palearctic raptor, experienced a severe population decline across its range during the 19th and 20th centuries, nearly disappearing as a breeding species in Spain. Although conservation and reintroduction efforts have facilitated recovery, information on its wintering ecology remains limited. We evaluated the population size and habitat selection of wintering Red Kites in and around the La Mancha Húmeda Biosphere Reserve (MHBR), Central Spain, and assessed whether survey route type affected detectability. Surveys comprised 325 vehicle-based line transects along paved roads and dirt tracks during the winters of 2021–2022 and 2022–2023, and the 2022 breeding season. Detection rates and density did not differ between route types. Across 212 winter transects, we recorded 124 individuals, with none detected during 113 breeding season transects. Density estimates were consistent across winters (1.3–1.4 individuals/km2), yielding a population estimate of approximately 1430 individuals. Habitat analysis indicated clear selection for open agricultural mosaics dominated by fallow land and vineyards, while rugged terrain was avoided. These results identify MHBR as an important wintering area. Yet, super-intensive agriculture is a poor habitat due to its uniformity. Enhancing heterogeneous open landscapes, including farmland, is essential for Red Kite colonization and expansion.

Birds doi: 10.3390/birds6040053

Authors: Tatjana Krama Ronalds Krams Didzis Elferts Colton B. Adams Dina Cirule Indrikis A. Krams

Antipredator behavior can vary consistently among individuals, yet links between proactive nest defense and passive fear strategies are rarely quantified in the wild. We tested whether hissing, a conspicuous, snake-like display at the nest, predicts tonic immobility (TI) and breeding success in female Great Tits (Parus major). In pine forests in southeastern Latvia (2023–2024), we presented a taxidermic Great Spotted Woodpecker (Dendrocopos major) at nest-box entrances during incubation and scored whether females hissed and how many calls they produced. The same females were later assayed for TI by brief supine restraint when nestlings were 3–4 days old. Of 141 incubating females, 105 (74.5%) hissed. TI duration differed sharply between groups: non-hissing females showed significantly longer TI than hissing females. Nest failure was significantly lower in hissing than non-hissing female nests. These results reveal a strong negative association between proactive defense and passive fearfulness, and they show that hissing can translate into higher reproductive success in a Woodpecker-dominated predator environment. We conclude that defense strategies covary within individuals along a personality axis and that predator community composition may shape selection on these strategies.

Birds doi: 10.3390/birds6040052

Authors: Allison A. Vestal-Laborde Rebecca C. Christofferson Kevin M. Ringelman Ashley M. Long

Coronaviruses (CoVs) were first described in poultry in the early 1930s and formally recognized as pathogens of both animal and human populations in the late 1960s. They are now considered among the most abundant viral families in the world. Though their distribution and diversity remain understudied in wild animals, representatives from 13 orders of wild birds worldwide have tested positive for CoVs of the gamma and delta genera over the last 25 years. Many of these wild bird species are in the orders Charadriiformes (shorebirds and their relatives) and Anseriformes (waterfowl including ducks, geese, and swans). Waterfowl are particularly concerning as potential reservoirs for CoVs because they are globally distributed; often congregate in large, mixed-species flocks; and may exist in close proximity to humans and domesticated animals. This review describes the history and current knowledge of CoVs in birds, provides an updated list of global detections of CoVs in 124 species of wild birds as reported in the peer-reviewed literature since 2000, and highlights topics for future research that would help elucidate the role of waterfowl in CoV transmission. Our review reiterates the need for continuous surveillance to detect and monitor CoVs across all bird species and for standardization in data reporting and analysis of both negative and positive results. Such information is critical to understand the potential role of free-ranging birds in the maintenance, evolution, and transmission of the virus. Further, we believe that research on the potential impacts of coronavirus infections and coinfections on avian demographics, especially reproduction in waterfowl, is warranted given known consequences in domestic poultry.

Birds doi: 10.3390/birds6040051

Authors: Alma Mikuška Sabina Alić Ivona Levak Jorge Bernal-Alviz Mirna Velki Rocco Nekić Sandra Ečimović Dora Bjedov

Environmental stressors, particularly agricultural pesticides, can influence both growth and physiology in developing birds, yet the relationship between morphometric condition indices and biochemical biomarkers remains poorly understood. We investigated body mass, beak length, tarsus length, and body condition index (BCI) alongside plasma and S9 biomarkers, including the activities of acetylcholinesterase (AChE), carboxylesterase (CES), and glutathione S-transferase (GST), as well as the levels of glutathione (GSH) and reactive oxygen species (ROS) in nestling White Storks (Ciconia ciconia) from Croatia. Bayesian undirected graphical model (BUGM) inferred a disconnected correlation structure composed of two communities, with a strong beak length–GSH association. Biomarkers further exhibited plasma-specific affinity: plasma markers reflected short-term adjustments, whereas S9 enzymes represented distinct metabolic pathways. Overall, morphometry and physiological status showed only limited integration, restricted mainly to plasma biomarkers, and residual body condition index did not serve as a reliable proxy for physiological stress. We conclude that integrated monitoring approaches, combining morphometric and biochemical profiling, provide a more nuanced assessment of nestling condition and strengthen the use of White Storks as sentinels of agroecosystem health.

Birds doi: 10.3390/birds6030050

Authors: Nikolay Yordanov Heinz Nabielek Kiril Bedev Pavel Zehtindjiev

Wind energy development is a key component in the transition to sustainable clean energy. Collision probability depends on turbine dimensions and species-specific behaviour, and understanding these relationships is essential for effective Environmental Impact Assessment (EIA). We applied a simulation approach based on flight-height distributions of a medium-sized diurnal raptor, the Common Buzzard (Buteo buteo). Long-term Global Positioning System (GPS) tracking data from an area with over 200 operating wind turbines in Northeastern Bulgaria were combined with Monte Carlo simulations of the Band collision risk model, and the predictions were validated against 18 years of systematic carcass searches under 114 turbines. Importantly, collision probability of the Common Buzzard was season-dependent, being greater during breeding and wintering, when flights occurred at lower altitudes, and lower during migration, when birds flew higher. Both the simulations and the field data supported an overall relatively low collision probability, indicating a high avoidance rate in this species. These findings suggest that wind energy planning should account for seasonal variation in flight behaviour and community composition, while long-term monitoring remains essential to ensure that cumulative impacts are adequately assessed.

Birds doi: 10.3390/birds6030049

Authors: William Gilbert

Cooperative breeding, or helping behavior, has long been recognized in birds. An ignored dichotomy, however, separates the helping found in many individuals of some long-lived, sedentary species from the helping occasionally found in the territories of isolated breeding pairs of some short-lived, long-distance migrant species. Both types of helping are called “cooperative breeding” in the literature. However, recognizing a dichotomy of “frequent” versus “infrequent” cooperative breeding would help justify the study of infrequent helping as a distinct discipline. Cooperative breeding in Wilson’s Warblers is infrequent, and among the unique behaviors found during this study were (1) solicitations by helper males, which aborted host male attacks and apparently initiated territorial acceptance, (2) an absence of sexual aggression between helper males and fertile host females, (3) attacks by helper males on intruding males during host female nest building, (4) helper males singing with impunity when host males were absent from territories, but being attacked when host males were present, and (5) a single male simultaneously serving as a helper in four adjacent host territories. Infrequent helping has essentially been ignored in studies and summaries of cooperative breeding. However, recognizing and studying infrequent helping as a distinct behavioral process could reveal interactions between helping and population ecology. Thus, infrequent cooperative breeding detected in a breeding population could reveal territorial saturation and could indicate that the population is likely ecologically healthy.

Birds doi: 10.3390/birds6030048

Authors: Les G. Underhill Magdalena Remisiewicz

For three regions of South Africa (Greater Gauteng, Greater Cape Town and Greater Durban) with the greatest coverage by bird atlas (SABAP2) fieldwork, we related arrival timing and abundance in each region of a long-distance migrant bird, the Barn Swallow, from July 2007 to March 2024. Using monotonic regression, from the atlas data we derived (1) the “annual anomaly of arrivals” from the average multi-year pattern; (2) the “average maximum” reporting rate at the completion of arrivals, in each region. We related these measures of the Barn Swallow timing and abundance in each of the 17 seasons of arrivals (July–January) in each of three region, with the large-scale climate indices, and temperature and precipitation in the Iberian+Apennine Peninsulas, for the Balkan Peninsula, and for the Sahel, averaged for the months when Barn Swallow visits areas between where these climate indices operate, at their breeding grounds in Eurasia, and along four southwards migration routes to South Africa. We used multiple regression modes with no more than two climate indices at a time, out of 84 explanatory variables, allowed by 17 data points (seasons) for each region. Our exploratory analysis indicated that the timing and abundance of Barn Swallow arrivals were related to a selection of these climate indices. The related climate indices varied between three regions in a pattern corresponding with the proportions of Barn Swallows arriving there from different breeding areas along different flyways, derived from an earlier study based on ringing recoveries. The paper shows the potential of the SABAP2 database as an annual monitoring approach, primarily due to the strong fieldwork protocol. We recommend that the project be continued indefinitely.

Birds doi: 10.3390/birds6030047

Authors: Michael A. Weston Kaori Yokochi

Anti-predator behaviour in birds is required by day and night but has barely been studied at night. For prey which detect predators visually, low light levels may diminish detection or monitoring of approaching threats. We conducted standardised approaches to Silver Gulls (Chroicocephalus novaehollandiae) by day and night along an urban foreshore in Melbourne, Australia, measuring light levels (Lux) experienced by the gull, Flight-initiation Distance (FID; the distance at which escape is initiated), and Starting Distance (the initial distance between the observer and the bird). We fitted models reflecting different conceptual possibilities for the relationship between Lux and FID. Support existed for a model with a stepwise effect of light on FID. Longer FIDs (i.e., earlier escape) in darker conditions suggest that gulls can detect an approaching threat in darkness at least as well as by day, but the tolerance of closer approaches may be diminished in dull and dark conditions, perhaps due to difficulty in monitoring an approaching threat and/or because nighttime represents a time of greater predator risk. Starting Distance was positively related to FID, a result commonly reported for many taxa by day.

Birds doi: 10.3390/birds6030046

Authors: Claudia Yeyetzi Salas-Rodríguez Carlos Lara Luis A. Sánchez-González Pablo Corcuera

Urbanization affects bird communities by reducing habitat and fragmenting ecosystems. Urban parks can help counteract these effects. However, anthropogenic noise can further alter bird composition. We examined the distribution and abundance of bird species in nine urban parks in Mexico City. We used a ten minute fixed-radius (25 m) point-counting technique to count birds along their annual cycle, with ten minutes allocated for bird counts. The quality of green areas was analyzed in terms of vegetation (Normalized Difference Vegetation Index), park size, and mean noise level dB(A) (based on MIN and MAX values), and species were grouped into trophic guilds. A total of 108 bird species were recorded, 5 of which are under special protection; we grouped all species into 14 trophic guilds, showing different responses to environmental gradients. Redundancy analysis (RDA) explained 89.98% of the variance, with noise and park size being the most influential variables. Granivores and omnivores were more tolerant to noise, while insectivores and frugivores preferred quieter areas with more vegetation. A positive association was observed between the presence of winter resident species and the park size. On the other hand, mean noise level dB(A) was negatively related to permanent resident species, winter resident species, and those with protected status. Conservation efforts should focus on maintaining ample green spaces and reducing noise pollution, as recorded high mean noise levels (>53 dB(A)) exceed the recommended thresholds for avifauna conservation.

Birds doi: 10.3390/birds6030045

Authors: Brygida Manikowska-Ślepowrońska Krzysztof Ślepowroński

Winter bird feeders provide high-energy food for birds when natural food resources are in short supply. We performed an experimental study including two treatments and a control to investigate the reactions of eight passerine species visiting a winter feeder to the presence of a predator or a food competitor, measured by the number of visits and foraging time. We included in analyses the age and sex of the most numerous species, the Great Tit (Parus major). Our results showed that the number of feeder visits per 30 min differed significantly among species, treatments (predator, competitor, or control), and time intervals of time elapsed from the start of the treatment. The presence of food competitors and predation risk significantly deterred the birds from feeding at the feeder. The number of visits to the feeder by Great Tits was significantly affected by age (more frequent visits by immatures), sex (more frequent visits by males), treatment (less frequent visits by immatures during predation risk and by adults during both experiments), and the time elapsed since the start of the experiment (more frequent visits by adult females during the first eight time intervals after the start of the experiment). Surprisingly, the duration of the foraging visits to the feeder was significantly influenced by species (lower for all tit species compared to the other visiting species) and the time elapsed since the start of the treatment (shorter foraging duration during the first nine time intervals for Hawfinch (Coccothraustes coccothraustes), European Greenfinch (Chloris chloris) and European Robin (Erithacus rubecula)), but not by the treatment itself. This suggests that the decision to use the feeder is risk-dependent, but when birds choose to forage, their foraging time is risk-independent.

Birds doi: 10.3390/birds6030044

Authors: Nurgul S. Sihanova Yerlan A. Shynbergenov Aiman B. Karabalayeva Nurila A. Togyzbayeva Sholpan B. Abilova

In order to determine the impact of urbanization on raptors in the semi-desert conditions of southwestern Kazakhstan, an analysis of the spatio-temporal distribution of raptors is presented for the first time based on the results of surveys of the avifauna of Kyzylorda. Eight species of raptors were recorded: field Hen Harrier (Circus cyaneus), Marsh Harrier (C. aeroginosus), Eurasian Sparrowhawk (Accipiter nisus), Long-Legged Buzzard (Buteo rufinus), Eurasian Buzzard (B. buteo), Steppe Eagle (Aquila nipalensis), Eurasian Hobby (Falco subbuteo), and Common Kestrel (F. tinnunculus). The probability of raptors being present was negatively associated with dense urban low-rise buildings with limited greenery in the bay and the new part of the city. At the same time, the dense urban development with little or no greenery in the old central part of the city provides adequate habitat (including a foraging base and nesting sites) for the Common Kestrel. Raptor presence was positively associated with the Syrdarya River floodplain and wasteland with small groups of trees and/or shrubs. The landfill site located on the north-eastern edge of the city serves as a feeding ground for the Long-Legged and Eurasian Buzzards, while the airport area is inhabited by the Eurasian Buzzard, Steppe Eagle, and Common Kestrel. Based on this study, we would recommend that enterprises (e.g., grain storage facilities, airports) and local executive bodies who are interested in the conservation of raptors and regulating the population of the pigeons around their territories should retain or plant more native vegetation and shrubs and preserve areas with green spaces.

Birds doi: 10.3390/birds6030043

Authors: Aida Vega Michael J. Yabsley Sonia M. Hernández Kayla B. Garrett Jose I. Aguirre Eva Banda

Urban landscapes have given rise to novel ecosystems (e.g., green areas), which differ in design and ecological quality depending on local planning strategies. Europe has the goal to increase conservation through increasing greenspace; however, urban wildlife health impacts, particularly on birds, are poorly studied. This study investigates associations between haemosporidians and intestinal coccidia in the Eurasian Tree Sparrow (Passer montanus), as well as their body condition and immunological status, from five urban green areas in Madrid, Spain, from 2019 to 2022. These green areas differ in green infrastructure, and because these birds are adapted to urban environments, they are a good model to evaluate how green area infrastructure may affect the birds’ health. We detected a 29% prevalence of haemosporidians (Haemoproteus being the most common, followed by Leucocytozoon and Plasmodium) and a 4% prevalence of intestinal coccidia. We found that haemosporidian prevalence was significantly higher in green areas with untreated stagnant water surrounded by muddy areas, ideal conditions for vector reproduction. Therefore, effective management strategies, especially related to water treatment, are essential for protecting urban wildlife and human health. This study provides valuable information for researchers and urban wildlife managers to incorporate appropriate management strategies into urban green area planning to preserve urban biodiversity and protect public health.

Birds doi: 10.3390/birds6030042

Authors: Vitor Araujo-Lima Rayane dos Santos Oliveira Marcio Mageski Rodrigo Barbosa Ferreira Charles Duca

The climate is expected to change substantially by the end of the current century. In response to climate change, species may disperse, adapt, or become locally extinct. We aim to assess how the climate changes predicted to occur by 2060 may affect the potential distribution of Tropical Mockingbird (Mimus gilvus antelius) and Chalk-browed Mockingbird (Mimus saturninus frater) within the Atlantic Forest domain, Brazil. Occurrence data for both species were compiled from the scientific literature and online biodiversity databases. A total of 118 georeferenced records were obtained for Tropical Mockingbird and 1080 for Chalk-browed Mockingbird. Species distribution models predicted that the two species would respond differently to the ongoing climatic changes. The Tropical Mockingbird will slightly expand its suitable habitat by 3.5% (3871 km2) under the optimistic scenario (minimum temperature increase by 2060; Representative Concentration Pathways-RCP 2.6) and 2.5% (2765 km2) in the pessimistic scenario (maximum temperature increase by 2060; RPC 8.5), relative to the 1960–1990 baseline. Chalk-browed Mockingbird will reduce its suitable habitat by 64% (70,780 km2) under RPC 2.6 and 65% (71,886 km2) under RPC 8.5. The two future climate scenarios suggest that sympatry between the two species will become increasingly rare, with a shift toward allopatry due to emerging climatically unsuitable areas separating their distributions. Our results highlighted the importance of environmental policies that incorporate local ecological contexts and species-specific traits to mitigate biodiversity loss under future climate conditions.

Birds doi: 10.3390/birds6030041

Authors: Anna Glushakova Aleksey Kachalkin

Public health in a densely populated city is inextricably linked to the state of the urban environment. The microclimate, the condition of water sources and sanitary well-being are just some of the many environmental factors that have a strong influence on people’s health. The presence of urban green spaces and various birds in cities is extremely important, also to create a more favorable psychological atmosphere for the people who live and/or work there. At the same time, it should not be forgotten that the feces of synanthropic birds are a favorable environment for various potentially pathogenic species of microorganisms, including yeasts of the genus Candida. Here, we investigated the culturable, potentially pathogenic ascomycetous yeast microbiome in the fresh and dry feces of five synanthropic birds (Rock Pigeon, European Starling, White Wagtail, Great Tit and House Sparrow). The samples were collected in spring (May 2024). In total, 48 Rock Pigeon, 47 European Starling, 38 White Wagtail, 32 Great Tit and 30 House Sparrow droppings were collected and analyzed. The selective medium Brilliance Candida Agar was used for cultivation. A total of 638 strains were isolated belonging to 9 yeast species (Arxiozyma bovina, Candida albicans, Nakaseomyces glabratus, Clavispora lusitaniae, C. tropicalis, C. parapsilosis, Pichia kudriavzevii, Debaryomyces hansenii and D. fabryi). All detected yeast species were molecularly identified using the ITS rDNA region. The microbiome of potential pathogens in fresh feces proved to be significantly host-dependent. Most pathogenic yeasts (7 species)—A. bovina, C. albicans, N. glabratus, Cl. lusitaniae, C. tropicalis, C. parapsilosis and P. kudriavzevii—were only detected in fresh feces from pigeons. This list contains five out of six ascomycetous species from the list of critical, high and medium-important yeast pathogens published in the World Health Organization fungal list. Of the potentially pathogenic yeasts, two species were observed in the dry droppings of various birds: C. parapsilosis and P. kudriavzevii. No significant differences in the diversity of culturable pathogens in dry droppings were observed between the different hosts. Fresh droppings from synanthropic birds, especially pigeons (and to a lesser extent dry droppings), therefore pose a health risk. In this study, we did not find any feces from synanthropic birds in which potentially pathogenic ascomycetous yeasts were not detected. To maintain the sanitary safety and well-being of citizens, it is very important to regulate the number of synanthropic birds (primarily pigeons), especially in sensitive areas such as playgrounds, hospital territories, etc.

Birds doi: 10.3390/birds6030040

Authors: Giampiero Sammuri Guido Alari Esposito Marta De Paulis Francesco Pezzo Andrea Sforzi Flavio Monti

This report presents the first complete natal dispersal trajectory of a female Montagu’s Harrier Circus pygargus, tracked in real time from fledging to first breeding using high-resolution continuous Global Positioning System (GPS) telemetry. The bird’s first flight occurred on 26 July 2024, initiating a 31-day post-fledging dependence phase (PFDP), followed by a 23-day pre-migratory phase (PMP), during which it explored areas up to 280.8 km from the nest and eventually settled ca. 190 km away in the Sirente-Velino Regional Park. From there, autumn migration began on 18 September 2024. The bird reached its first wintering site in Mali by 15 October. It used four wintering areas over 178 days, with a winter home range of 37,615.02 km2. Spring migration started on 11 April 2025 and lasted 21 days, ending with arrival in the Gran Sasso e Monti della Laga National Park (Central Italy) on 2 May. The bird used two main sites during the pre-breeding phase (PRBP) before laying eggs on 2 June 2025. The natal dispersal distance, from birthplace to nest site, was 151.28 km. Over 311 days, it covered a total of 14,522.23 km. These findings highlight the value of advanced telemetry in revealing early-life movement ecology and are useful for understanding species-specific patterns of survival, reproduction, and space use and can inform conservation actions.

Birds doi: 10.3390/birds6030039

Authors: Dirk H. R. Spennemann

This paper outlines a methodology to compile geo-referenced observational data of Australian birds acting as pollinators of Strelitzia sp. (Bird of Paradise) flowers and dispersers of their seeds. Given the absence of systematic published records, a crowdsourcing approach was employed, combining data from natural history platforms (e.g., iNaturalist, eBird), image hosting websites (e.g., Flickr) and, in particular, social media. Facebook emerged as the most productive channel, with 61.4% of the 301 usable observations sourced from 43 ornithology-related groups. The strategy included direct solicitation of images and metadata via group posts and follow-up communication. The holistic, snowballing search strategy yielded a unique, behavior-focused dataset suitable for analysis. While the process exposed limitations due to user self-censorship on image quality and completeness, the approach demonstrates the viability of crowdsourced behavioral ecology data and contributes a replicable methodology for similar studies in under-documented ecological contexts.

Birds doi: 10.3390/birds6030038

Authors: Nevena Kolarova Christoffer Sjöholm Jannika Boström Susanne Åkesson Mihaela Ilieva

Feather mites play an important role in bird communities, covering a wide spectrum of associations with their hosts, ranging from parasitic to mutualistic relations. As a result of long co-evolution with their warm-blooded hosts, this diverse group of arthropods can be found in a wide range of environments where their hosts occur, including the high Arctic. The feather mite fauna of Greenland is poorly known. Herein, we present new data on feather mites found on three species of passerine birds, which were captured on Disko Island (Qeqertarsuaq), West Greenland. The feather mite species Analges longispinosus was found on Snow Bunting (Plectrophenax nivalis); Proctophyllodes plectrophenax on Snow Bunting and Lapland Longspur (Calcarius lapponicus); and Proctophyllodes hipposideros on Northern Wheatear (Oenanthe oenanthe). The two Proctophyllodes species represent new records for Greenland. Further studies are needed to reveal the diversity of feather mite species in this remote Arctic region.

Birds doi: 10.3390/birds6030037

Authors: Carla Suertegaray Fontana Lucilene Inês Jacoboski Jonas Rafael Rodrigues Rosoni Juliana Lopes da Silva Filipe Augusto Pasa Bernardi Pamela Eliana Malmoria Christian Beier Sandra Maria Hartz

The Brazilian Araucaria Forest (AF) now covers only 1% of its original extent due to significant degradation, making conservation a challenge. The AF occurs in a mosaic alongside grassland and Atlantic Forest ecosystems, influencing bird species’ distribution through ecological processes. We compared the composition and functional diversity of the bird community along a gradient of AF cover in a protected area (Pró-Mata Private Natural Heritage Reserve) in southern Brazil. Bird sampling was conducted using MacKinnon lists along five trails with different histories of vegetation suppression, based on forest cover estimates from landscape imagery. Birds were functionally classified based on morphological and ecological traits. We recorded 191 bird species in total. We found higher bird richness in trails with less forest cover, while functional diversity responded inversely to vegetation cover. Bird species composition shifted from more open-habitat specialists to more forest specialists with the increasing forest cover and vegetation structural complexity. These findings highlight the ecological importance of maintaining vegetation heterogeneity, as vegetation mosaics enhance avian species richness and support a broader range of functional traits and ecosystem processes. We recommend the conservation of Araucaria Forest–grassland mosaics as a strategic approach to support multidimensional biodiversity and sustain key ecological functions in southern Brazil.

Birds doi: 10.3390/birds6030036

Authors: Claudia Itzel Beteta-Hernández Iriana Zuria Pedro P. Garcillán Luis Felipe Beltrán-Morales María del Carmen Blázquez Moreno Gerzaín Avilés-Polanco

In this study, we used a causal analysis approach to assess the impact of deforestation on bird abundance in Mexico. Based on records in the eBird and GBIF databases, ten species were selected in 807 grids on the mainland. Relative abundances by species were estimated using a fixed-effects panel data regression for the period 2016–2018. Deforestation was used as a quasi-natural experiment, classifying treatment and control groups according to the distribution of relative abundances by quintiles of gross deforestation rates during the period 2001–2018. The treatment group was defined as relative abundances of birds present in grids in the last deforestation quintile (≥4% to 12%); the control group included relative abundances of birds present in grids of the first four quintiles (<4%). Extended regression models were used to estimate the impacts of high deforestation rates on the relative abundance of birds, finding mixed causal effects: five showed statistically significant declines in abundance (Ruddy Ground Dove (Columbina talpacoti), Black Vulture (Coragyps atratus), Melodious Blackbird (Dives dives), Bewick’s Wren (Thryomanes bewickii), and Rufous-backed Thrush (Turdus rufopalliatus)), while one specie Yellow-winged Cacique (Cassiculus melanicterus) exhibited significant increases. These findings highlight the importance of causal effect studies in contributing to empirical evidence-based conservation decision-making.

Birds doi: 10.3390/birds6030035

Authors: Hyago Keslley de Lucena Soares Vanessa Moura dos Santos Suellen da Silva Santos Reinaldo Farias Paiva de Lucena

How humans perceive and interact with other animal species is critical in enhancing conservation initiatives. The study recorded and analyzed people’s knowledge and perceptions of birds of prey and their interactions in three rural communities in Paraíba, Brazil. The data were collected by face-to-face interviews using semi-structured questionnaires. One hundred ninety-one people were interviewed, and 19 species were recorded. Based on the answers to the questionnaires, the species are considered omens of climatic/ecological and supernatural events. They are important in the maintenance of ecosystems (predation of rodents and snakes and feeding on dead animals). However, most birds of prey are killed because they cause damage by preying upon domestic animals or for being associated with bad omens. The diversity of information listed here shows the need for complex and interdisciplinary studies to understand the human dimensions of knowledge and relationships between people and birds, contributing to species conservation and encouraging coexistence between people and birds of prey.

Birds doi: 10.3390/birds6030034

Authors: Kevin J. McGraw Victor Aguiar de Souza Penha Kathryn N. DePinto Dean J. Drake Elise Crawford-Paz Soldán Danielle Pais

Real-time health assessment is crucial for diagnosing emerging threats to wildlife. Point-of-care instruments now allow detailed, affordable measurements of blood metabolites (e.g., glucose, triglycerides, ketones) in free-ranging animals. Ketones, however, remain understudied, especially in relation to environmental and life-history traits. Here, we assessed blood ketone variation in male House Finches (Haemorhous mexicanus) across two seasons (summer and winter) as a function of body condition, circulating glucose, carotenoids, lipid-soluble vitamins, and habitat urbanization (urban/suburban/rural). In both seasons, the interaction between capture site and glucose concentration predicted ketone levels: urban and suburban birds showed a negative relationship, while in summer, rural birds showed a positive one. Additionally, in winter, ketone levels were negatively associated with plasma carotenoids, indicating birds with higher carotenoid levels had lower ketone concentrations. These findings suggest that similar to patterns seen in biomedical research and our previous work on carotenoids and health, ketone status can serve as a valuable indicator of nutritional condition and fat metabolism in wild birds, particularly in the context of urbanization.

Birds doi: 10.3390/birds6030033

Authors: Isabela Tapia-Jaramillo Joel Arica Alejandra Espín Víctor Carrión Juan Pablo Mayorga Christian Sevilla Eliécer Cruz Paola Sangolquí

The Galápagos Petrel (Pterodroma phaeopygia) is a long-lived Critically Endangered seabird endemic to the Galápagos Islands and faces severe threats from invasive species, particularly rodents. Until now, evidence of rat predation on Galápagos Petrel nestlings has been largely indirect, inferred from indirect evidence and predator control outcomes. Here, we present the first photographic documentation of a presumed black rat (Rattus rattus) preying on a Galápagos Petrel nestling, captured by a camera trap on private farmland on Santa Cruz Island. The predation event occurred during a period of parental absence, when the nestling was left unattended while adults foraged at sea. Notably, the parent Petrels continued returning to the nest for 91 days following nestling loss, suggesting strong nest fidelity and highlighting potential energetic costs associated with breeding failure. Our findings reveal critical vulnerabilities during the nestling-rearing phase and emphasize the urgent need to enhance rodent control efforts and protect nesting areas, particularly on farmland outside the Galápagos National Park boundaries. We conclude by providing targeted conservation recommendations to mitigate invasive predator impacts and improve breeding success for this emblematic and imperiled seabird.

Birds doi: 10.3390/birds6030032

Authors: Grzegorz Zawadzki Dorota Zawadzka

The grey-headed woodpecker (Picus canus) (GHW) is one of the least-studied European woodpeckers, listed in Annex I of the Birds Directive. We examined the key environmental characteristics that determine the possibility of GHW occurrence in vast forests in northeast Poland. Woodpeckers were inventoried in spring on 54 study plots (4 km2) covering 20% of the forest area. Active territories were detected and mapped using the playback experiment of territorial voices and drumming. The generalized linear model GLM, random forest RF, and Boosting were used for modeling. GLM was used to indicate the most critical factors affecting the abundance of GHW. The number of territories in a single study plot ranged from 0 to 3; the most frequent were areas without woodpeckers. The probability of the nesting of the GHW was increasing at plots with watercourses, a bigger share of mixed forest area, and a proportion of stands over 120 years old. The calculation for all 400 quadrats allowed us to estimate the population size at approximately 180–200 breeding pairs. The overall density of GHW in the study area was assessed at 0.13/km2, while at the optimal quadrats, it increased to about 0.75/km2. Preference for watercourses was linked to alders growing along water banks. Near the water, there are often small meadows where the GHW can prey on ants. In turn, old-growth forests above 120 years old increased the probability of the presence of the GHW. There are more dead and dying trees in older forests, which are the ones the GHW chooses to excavate cavities. To effectively protect the habitats of the GHW, it is necessary to maintain a larger area of stands over 120 years old, mainly on wet sites.

Birds doi: 10.3390/birds6020031

Authors: Melissa Alves Rodrigues Paulina Lesiczka Maria da Conceição Fontes Luís Cardoso Ana Cláudia Coelho

Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is an emerging zoonotic pathogen with a high case fatality risk. Its primary vectors, Hyalomma spp. ticks, are expanding their geographic range, raising concerns about the increasing risk of Crimean-Congo Haemorrhagic Fever (CCHF) outbreaks in Europe. Migratory birds contribute considerably to the spread of Hyalomma ticks, transporting immature forms over long distances during spring migrations. Additionally, climate change plays a crucial role in this expansion by creating favorable conditions for Hyalomma spp. survival and dispersal. This review explores the interplay between Hyalomma spp. ecology as vectors of CCHFV, the role of migratory birds and the impact of climate change on the dispersal of CCHFV across Europe. Understanding these dynamics is essential for assessing future risks, improving surveillance strategies, and implementing effective public health interventions.

Birds doi: 10.3390/birds6020030

Authors: Attila Bende Sándor Faragó Richárd László Viktória Csanády István Fekete Tibor Pecsics László Bozó

Based on samples collected in the framework of the Eurasian Woodcock Bagging Program in Hungary between 2010 and 2019, we investigated the spring migration of Eurasian Woodcock by age class and sex. The dynamical properties of each year’s trajectory are represented using Gaussian smoothing. The models were used to determine the peak of the migration by sex and age in each year. In the comparative analysis by sex, an ARIMA regression model was used as a time-series analysis, which showed that there was a strong positive correlation between the migration of females and males in each year, which indicates that there is no statistically verifiable time difference in the migration pattern of each sex. We found a positive correlation in the same ARIMA model for each year of migration, which indicates that there is no statistically verifiable difference in the spring migration of males and females of the same age groups in Hungary. This study also demonstrates that there is a sharp ratio shift in the spring migration in favour of males. This significant imbalance can be explained by the selective hunting during spring roding, which is of particular importance for the sustainable utilisation of the species.

Birds doi: 10.3390/birds6020029

Authors: Antonio-Román Muñoz Darío Delgado Pablo Ortega Julio Ortega Antonio Sepúlveda Pedro Barón Eva Bratek Javier Elorriaga Cristina Malia Ricky Owen Miguel Puerta Alejandra Cerezo Juan Ramírez Yeray Seminario Miguel González

Range expansions driven by global warming are increasingly documented, particularly in birds and insects. The House Bunting, a species native to North Africa, has recently established the first confirmed breeding population in mainland Europe in Algeciras, southern Spain. This study presents the results of the first systematic survey of this population, conducted in December 2024. Using a standardized survey method across a grid of hexagonal sampling units, we recorded a minimum of 18 individuals, including juveniles, indicating both successful reproduction and possible new arrivals. Observations were concentrated in low-rise urban areas, mirroring the species’ preferred habitats in Morocco. The presence of individuals with juvenile plumage in December suggests an extended breeding season, which may facilitate population growth. Given the geographical proximity to North Africa and predicted increases in aridity due to climate change, further expansion into Iberia appears likely. Although no immediate ecological impacts have been detected, the potential for interactions with resident species justifies continued monitoring. This study provides a baseline for assessing the establishment and growth of this population, contributing to a broader understanding of how climate change influences species distributions and the colonization dynamics of expanding bird populations.

Birds doi: 10.3390/birds6020028

Authors: Prateek Dey Kochiganti Venkata Hanumat Sastry Ram Pratap Singh

The genus Coturnix, comprising migratory Old World quails, includes Common Quail (Coturnix coturnix) and Japanese Quail (Coturnix japonica), which are nearly indistinguishable morphologically. This similarity poses challenges in species identification, leading to conservation issues such as the illegal trade of wild Common Quail in the name of farmed Japanese Quail. To address this issue, we employed two approaches: (1) mining species-specific short sequence repeats (SSRs) and (2) designing a PCR-restriction fragment length polymorphism (PCR-RFLP) assay targeting the COX1 gene to distinguish these species. While SSR markers proved unreliable, the PCR-RFLP assay successfully distinguished between Common Quail and Japanese Quail, leveraging the unique BsaBI restriction site in the Common Quail COX1 gene. This method demonstrated high specificity and reproducibility, offering a robust tool for forensic and conservation applications. Our findings provide a reliable, efficient, and accessible technique for wildlife managers and researchers to regulate the illegal trade of Coturnix quails and support conservation efforts.

Birds doi: 10.3390/birds6020027

Authors: Colton B. Adams Ronalds Krams Didzis Elferts Guntis Brūmelis Iluta Dauškane Linda Strode Agnis Šmits Giedrius Trakimas Indrikis A. Krams Tatjana Krama

When selecting a habitat, it is optimal for organisms to choose one that maximizes reproductive success through access to high-quality resources, particularly in species that engage in parental care. However, organisms may inadvertently select a habitat for breeding that would initially appear preferential and undamaged, but may, in reality, be detrimental to parent and/or offspring fitness. In this study, we tested whether migratory European Pied Flycatchers (Ficedula hypoleuca) nesting in forest patches affected by outbreaks of the great web-spinning sawfly (Acantholyda posticalis) experienced fitness reductions indicative of an ecological trap, compared to those nesting in unaffected forest patches. After installing nest boxes to attract breeding pairs and potentially combat the outbreak, we found that Flycatchers inhabiting areas with sawfly outbreaks had similar clutch sizes to pairs breeding in unaffected forest patches. Contrarily, the fledgling number and body condition were significantly lower for those nesting in the damaged forests. In providing nest boxes for migrating Flycatcher pairs in forest patches that were subsequently impacted by a pest insect outbreak, an ecological trap arose for those pairs choosing to nest in what appeared to be an unaffected forest at first. Given the inability of breeding pairs to distinguish habitat quality on initial inspection, we suggest that nest boxes be used with caution in areas with unfavorable habitat conditions when attracting migratory birds, given the trends of their declining global numbers.

Birds doi: 10.3390/birds6020026

Authors: Asad Ullah Sumaira Shams Sultan Ayaz Eliana Ibáñez Arancibia Unays Siraj Patricio R. De los Rios-Escalante Taqi Ullah Farhad Badshah

Ecological determinants of avian population dynamics are essential for effective wildlife management and conservation. Black and grey francolins are classified as being of least concern by the IUCN and are an ecologically significant bird in the northern regions of Pakistan. Although habitat degradation and overhunting have adversely affected their populations, research on the population structure and habitat preferences of the Totali Game Reserve, Buner District, Pakistan, remains limited. The present study applied distance sampling via the line transect method to estimate population densities and the quadrat method to assess vegetation characteristics across three distinct habitats. A statistical analysis revealed significant variations in densities across the three habitat types—agricultural lands, agroforests, and pasturelands—with both species exhibiting distinct preferences for pastureland ecosystems. Seasonal trends indicated that autumn represented the peak period for the population, driven by post-breeding surges and optimal habitat conditions. Moreover, both species demonstrated a strong affinity for habitats dominated by specific plant species, including hopbush, raspberry, barberry, and blackberry, which provide a critical resource for food, foraging, nesting, and shelter. These findings highlight the ecological importance of pasturelands and specific vegetation types for supporting the survival of these species. Furthermore, conservation efforts should prioritize the preservation and restoration of pastureland ecosystems and incorporate rigorous monitoring programs to guide adaptive management strategies aimed at mitigating population declines.

Birds doi: 10.3390/birds6020025

Authors: Christiane Böhm Molinia Wilberger Armin Landmann

We analyse data from a rescue database collected at the Innsbruck Alpenzoo (Tyrol, Austria). The sample covers 33 years (1988–2020), and more than 5250 wild birds from 145 species originating from Innsbruck and the surrounding Inn Valley, one of the most densely populated areas in Europe. Both, the total number of birds as well as the number of bird species yearly admitted have increased since 1988. Orphaned nestlings and victims of glass collisions were the most common reasons for admission and responsible for the increase. Species’ susceptibility to accidental causes increased with regional abundance and degree of urbanisation. More urbanised species are characterised by a high proportion of nestlings and juveniles in the sample. The seasonal patterns of deliveries in these species show a peak in the late breeding season, and young birds are particularly susceptible to glass collisions and cat attacks. The species list also includes regionally rare wetland, upland and forest breeders and foreign migrants. Such species show a high proportion of admissions in autumn and collisions with windows play a greater role for short-distance migrants. Our data also suggest that small birds (<15 g body mass) are more likely to collide with glass panes than larger species. In conclusion, our data suggest that basically all bird groups and species are at least occasionally affected by human structures and activities in urbanised landscapes but support the notion that juveniles and migrants are more prone for accidents due to the lack of experience with anthropogenic structures in new areas.

Birds doi: 10.3390/birds6020024

Authors: Yanina Poblete Carolina Fernández Cristian R. Flores Patricia Vega Miguel Ávila

Exploratory behavior involves gathering information and reflects how individuals interact with their environments. In seasonal environments, individuals undergo environmental cycles that might lead to differences in this behavior between locations and seasons. Here, we compare the exploratory behavior measured during an open-field test in 102 adult individuals of rufous-collared sparrow (Zonotrichia capensis) from three locations in central and southern Chile. A generalized mixed-effect model (GMM) was utilized to compare the exploratory behavior between locations and seasons. The two-way interaction between both variates was also included. Body mass and sex were included as covariates and elevation of the study sites as a random effect. The result indicates that exploratory behavior significantly varied between populations and seasons. Specifically, birds tested in the Chilean central zone (33° S) and breeding birds showed higher exploration scores during the open-field test than birds tested in the southern zone (38° S) and non-breeding birds. These findings suggest that exploratory behavior may be driven by local environmental pressures, underscoring the role of weather and seasonality in shaping this behavior.

Birds doi: 10.3390/birds6020023

Authors: Lucas M. Leveau

The flock formation of bird species is a crucial behavioral process that enables them to colonize urban areas. However, the factors influencing the structure and composition of ground-feeding bird flocks have not yet been analyzed. This study aimed to relate flock characteristics, including size, number, species richness, and composition, to local and landscape factors in the urban parks of Buenos Aires City, Argentina. Surveys of flocks were conducted in 16 parks during the breeding season, covering both mono-specific and mixed-species flocks. Flock numbers were positively correlated with tree, lawn, and bare ground cover but negatively associated with raptor presence in the parks. Flock species richness declined with increased noise and pedestrian traffic but rose in parks where raptors were present. The composition of species in flocks was linked to tree cover, noise, and the presence of raptors. While the Rock Dove (Columba livia) and the Rufous-bellied Thrush (Turdus rufiventris) were more abundant in parks with greater tree cover, the Eared Dove (Zenaida auriculata) and the Monk Parakeet (Myiopsitta monachus) showed increased abundance in more open parks. Zenaida auriculata and Columba livia experienced a decline in abundance in parks where raptors were present. Our findings indicate that resource availability and predation risk are crucial factors shaping flock formation in urban parks.

Birds doi: 10.3390/birds6020022

Authors: Jukka Jokimäki Marja-Liisa Kaisanlahti-Jokimäki

Urbanization changes the environment through physical constructions, disturbances, and altered resource availability. These modifications influence both prey and predator assemblages. Several studies have indicated that hole-nesting birds outnumber ground nesters in cities. Differential nest predation can be one reason behind this observation. We conducted a multi-year artificial nest predation experiment along an urban gradient by using artificial ground nests and nestboxes in Rovaniemi, Finland. Because visually searching avian predators dominate in cities, we predicted that nest predation of ground nests will increase with urbanization, whereas nests in holes will be better protected than ground nests. Ground nest predation increased with urbanization, being lowest in forest and rural areas, intermediate in suburban area and highest in urban area. However, there was no year-effects on artificial ground nest predation, suggesting that even a single-year results of artificial nest predation experiment can be reliable. In the city, ground nest predation was greater than nestbox predation. In forests, nestbox predation was greater than ground nest predation. Among ground nests, predation was greater in the city than in forests. Among nestboxes, predation was greater in forest than in urban or suburban habitats. Only the ground nest predation was greater in managed than in un-managed parks. Ground nest predation decreased with tree cover and increased with the patch area. No variables were entered in the models of the nestboxes. The results indicated that ground nesters might avoid urban areas as nesting sites. We assume that visually searching avian predators benefit from the lack of covering vegetation in city parks. However, because most avian nest predators, like corvids, are not effective nest predators of hole-nesting birds, urban areas are safe nesting areas for hole-nesters. The results suggest that nest predation is one important factor that could explain, why hole-nesting bird species outnumbered ground-nesting species in cities. The result give support for the hypothesis that nest predation pressure can modify urban bird assemblage structure.

Birds doi: 10.3390/birds6020021

Authors: Ezra Hadad Reuven Yosef

Our study investigates predation among sympatric owl species in the Judea Region, specifically focusing on the predation by Eurasian Eagle Owls (Bubo bubo) on smaller owl species. Field observations conducted between 2006 and 2009 revealed recurrent predation events, with 172 individuals documented as preyed upon by Eurasian Eagle Owls. These results align with previous studies, demonstrating the role of larger owl species as intraguild predators that affect the survival and reproduction of smaller owls. Our findings emphasize the need for further research on intraguild predation and its ecological consequences. This study contributes to a broader understanding of the complex interactions within nocturnal raptor communities and underscores the importance of incorporating such dynamics into conservation strategies to safeguard owl biodiversity in fragmented landscapes.

Birds doi: 10.3390/birds6020020

Authors: Paula Sabrina Bronze Campos Benilson Silva Rodrigues Anderson José Baia Gomes Rodrigo Petry Corrêa de Sousa Edivaldo Herculano Corrêa de Oliveira

Anseriformes represent a basal order in the phylogeny of neognath birds and are of particular interest in cytogenetic research due to their distinctive chromosomal features. However, aspects of their chromosomal evolution, such as the distribution and organization of microsatellite sequences, remain poorly understood. Given the role of these dynamic repetitive sequences in chromosome organization, differentiation, and evolution, we analyzed microsatellite distribution in three Anatidae species, each representing a different subfamily: Amazonetta brasiliensis-Brazilian Teal (Anatinae), Coscoroba coscoroba-Coscoroba Swan (Anserinae), and Dendrocygna viduata-White-faced Whistling Duck (Dendrocygninae). This is the first karyotypic description for White-faced Whistling Duck (2n = 78) and Brazilian Teal (2n = 80), whereas Coscoroba Swan, previously analyzed, exhibits a notably high diploid number (2n = 98). Despite sharing a similar macrochromosome morphology, the three showed differences in diploid numbers and microsatellite distribution. Extensive microsatellite accumulation was found in both autosomal and sex chromosomes (Z and W) of Brazilian Teal and Coscoroba Swan, while White-faced Whistling Duck displays minimal hybridization signals and an absence of microsatellites on the sex chromosomes. The accumulation of specific microsatellites, such as (CAC)10 and (GAG)10, in centromeric and pericentromeric regions suggests an association with transposable elements, potentially driving chromosomal evolution. Notably, the substantial accumulation of these sequences on the Z and W chromosomes of Brazilian Teal and Coscoroba Swan, but not White-faced Whistling Duck, supports the hypothesis that repetitive sequence expansion occurs in a species-specific manner, contributing to sex chromosome differentiation. These findings highlight microsatellite mapping as a valuable tool for understanding chromosomal evolution and genomic differentiation in Anseriformes.

Birds doi: 10.3390/birds6020019

Authors: German Miguel Quijano-Chacón Sarahy Contreras-Martínez Verónica Carolina Rosas-Espinoza Oscar Gilberto Cárdenas-Hernández María Faviola Castillo-Navarro

Prescribed fires are a management strategy involving the controlled application of fire to achieve specific ecological objectives. In the pine–oak forests in west-central Mexico, we conducted an experimental low-severity prescribed fire to assess its effects on hummingbird diversity. We hypothesized that low-severity prescribed fire would enhance both taxonomic and functional diversity by modifying understory vegetation structure and increasing floral resource availability. To test this, we performed point count censuses in both low-severity prescribed fire and fire-suppressed sites where wildfire had been excluded for over 40 years. Taxonomic diversity was assessed using Hill numbers to estimate true diversity across different abundance weights, while functional diversity was evaluated through indices such as functional richness, functional evenness, and functional divergence. Our results indicated that low-severity prescribed fires did not affect overall hummingbird diversity as both low-severity prescribed fire sites and fire-suppressed sites exhibited comparable species richness. However, sites with low-severity prescribed fire and concave summits showed a significantly higher abundance of common and highly abundant species. Notably, species richness did not align with functional richness, as the fire-suppressed site exhibited the highest functional diversity. These findings suggest that hummingbird community structure is influenced by a combination of fire history, topography, vegetation structure, and floral resource availability. We recommend maintaining a heterogeneous forest matrix, incorporating patches with fire suppression, and areas subjected to prescribed fires of varying severity. This multifaceted approach enhances both taxonomic and functional biodiversity, promoting habitat heterogeneity and ensuring the persistence of diverse hummingbird assemblages in fire-prone ecosystems.

Birds doi: 10.3390/birds6020018

Authors: Jorge Enrique Ramírez-Albores

Habitat loss, pollution, and climate change have a global impact on bird diversity, particularly in central Mexico, where human disturbances and unplanned urbanization can lead to the decline of this faunal group. In this study, the effects of season (rainy, warm–dry, or cool–dry) and environmental variables (size, perimeter, vegetation cover, built cover, distance to nearby greenspaces and distance to the closet natural vegetation patch) on the avian diversity at different sites located in a peri-urban landscape in the Metropolitan Area of Mexico City were determined. The study was conducted using the linear transect method to assess the diversity and composition of bird communities from November 2019 to March 2022, recording 290 total bird species. Zumpango Lagoon was the study site with the highest diversity (N = 209, H′  =  3.22) and evenness index (J′  =  0.76). Linear mixed models were used to determine the effects of season and environmental variables of the study sites on the avian diversity. The effect of distance to the nearest greenspace was significantly more positive during the rainy season than the two dry seasons. An ANOSIM test also showed that the avian community associated with water bodies differed significantly from the other communities (R = 0.16, p < 0.001). Despite some anthropogenic activities and human intrusion, sites with water bodies retain a high diversity of birds. This finding indicates the need for immediate conservation efforts to protect many resident breeding species and wintering migratory birds in the study area.

Birds doi: 10.3390/birds6020017

Authors: Cassie Rueda Kevin J. McGraw

Due to continuing worldwide urban expansion, research into how urban environments affect local flora/fauna has grown significantly. Studies on the impacts of urbanization on birds have explored a wide variety of behaviors (e.g., foraging, breeding, migratory), but there is little research on the impacts of cities on avian coloniality. Various urban-environmental factors may impact colonial birds. The predominance of impervious surfaces in cities, for example, has been associated with the decline of several bird species due to negative effects on availability and quality of habitat. The urban heat island effect and shifts in resource availability (e.g., food, water) may also affect colonial birds. Here, we used five years of community-science data available in eBird to investigate urban impacts on group size in Cliff Swallows (Petrochelidon pyrrhonota), an abundant colonial bird species that now breeds readily under bridges and other built structures over or near water in Phoenix, Arizona, USA. We hypothesized that, based on the colonial breeding habits of these neotropical migratory birds in this desert environment, swallows in Phoenix would form larger groups in areas with more food and water sources and with more built structures. In fact, we found that proximity to water sources and cropland, but not impervious surface density, was positively and significantly related to group size. These results suggest that, in this desert ecosystem, an abundance of food/water resources provided by humans permits Cliff Swallows to form larger social groups during breeding. Although many studies show harmful impacts of cities on local wildlife, our findings highlight how urban and/or agricultural ‘oases’ may relieve some native species from natural resource limitations and permit them to thrive and increase in group size in human-impacted environments.

Birds doi: 10.3390/birds6020016

Authors: Asad Ullah Sumaira Shams Sultan Ayaz Eliana Ibáñez-Arancibia Unays Siraj Patricio R. De los Rios-Escalante Farhad Badshah

Limited research exists on the breeding ecology of the black francolin (Francolinus francolinus) in northern Pakistan. This study assessed egg dimensions, clutch size, hatching, fledging, and overall breeding success across different habitats and nests (n = 25) at Totali Game Reserve, Buner. Generalized linear models (GLMs) were used to analyze the effects of nest site characteristics and nest traits on breeding parameters. Egg dimensions were consistent across sites whereas bush nests had slightly wider eggs. The average clutch size was 5.9 ± 1.7 eggs, with an average of 4.8 ± 1.0 hatchlings per nest. A total of 111 chicks fledged, averaging 4.4 ± 1.0 per nest, yielding an overall breeding success rate of 75.5%. Nests containing six eggs had higher hatching success (76.6%). GLMs results showed a significant positive relationship between clutch size and hatchling, while nest site and traits had no significant effects. However, fledgling success was positively influenced by hatchling numbers, with nests in wetland habitats yielding significantly more fledglings (4.6 ± 0.9) than those from dryland habitats (4.0 ± 1.2). These findings suggest Black Francolins prefer nesting in wetland areas in bushes, likely due to better protection and favorable conditions.

Birds doi: 10.3390/birds6020015

Authors: Fabien Beaumont Sébastien Murer Fabien Bogard Guillaume Polidori

While the formation flight of birds offers numerous benefits, such as reduced predation risk, improved orientation, and enhanced communication, the aerodynamic interactions between birds are not fully understood due to their inherent complexity. This study explores the wake vortex dynamics of two flying birds and their influence on aerodynamic forces, based on their relative positions in a group. Using a computational finite volume method, the 3D vortex patterns in the wake of Canada Geese (Branta canadensis) flying at 1000 m altitude and 13.9 m/s airspeed were modeled. The results reveal a complex, undulating vortex structure shaped by the wingbeat amplitude and frequency. The analysis shows that trailing birds positioning their wingtips within the upwash region of vortices that are generated by a leading bird significantly reduce drag and enhance lift, achieving up to a 32% improvement in aerodynamic efficiency, calculated as the lift-to-drag ratio. An optimal separation distance of approximately one wavelength (3.47 m) between birds has been identified, leading to a 7% reduction in both mean drag force and aerodynamic power requirements. These findings, extrapolated to larger bird groups, offer valuable insights into the organization and optimal positioning of birds flying in V-formations, advancing our understanding of collective flight dynamics.

Birds doi: 10.3390/birds6010014

Authors: Akshit R. Suthar Alan R. Biggs James T. Anderson

Despite increasing conservation efforts for shorebirds, there are widespread declines in many shorebird species in North America. Climate change is causing significant shorebird range shifts and population declines. This study investigates the relationship between meteorological variability and shorebird population dynamics over ten years (2014–2023) at Fish Haul Beach, Hilton Head Island, South Carolina, USA. Shorebirds, reliant on specific habitats for breeding and foraging, are increasingly vulnerable to climate-driven changes, including shifts in temperature, precipitation, and wind speed. Using Generalized Additive Models with Poisson distribution, we analyzed species-specific count data for 12 shorebird species in relation to annual meteorological variables. Additionally, the Mann–Kendall test and Sen’s slope were employed to assess decadal trends in population counts. The results reveal significant declines in Black-bellied Plover (Pluvialis squatarola), Marbled Godwit (Limosa fedoa), and Willet (Tringa semipalmata). In contrast, Semipalmated Plover (Charadrius semipalmatus) and Piping Plover (Charadrius melodus) showed increasing trends, indicating potential habitat benefits or conservation success. Temperature emerged as a key driver affecting the abundance of several species, while precipitation and wind speed also played crucial roles in shaping population dynamics. Our findings underscore the sensitivity of shorebird populations to weather fluctuations, emphasizing the need for integrating meteorological variability into management strategies to ensure shorebird conservation. This study provides critical insights into the impacts of meteorological variables on migratory shorebird populations along the Atlantic Flyway. It highlights the importance of maintaining healthy coastal ecosystems in South Carolina.

Birds doi: 10.3390/birds6010013

Authors: Arno Reinhardt Moritz Mercker Maike Sabel Kristina Henningsen Frank Bernshausen

Anthropogenic structures such as overhead powerlines pose potentially high collision risks to flying animals, particularly birds, leading to millions of fatalities each year. Studies of bird collisions with powerlines to date, however, have estimated different numbers of collision per year and per kilometer in highly variable landscapes. This study aimed to clarify the risk of bird collisions with powerlines in an average landscape, to overcome the bias towards studies in collision hotspots. We conducted experiments to determine searcher efficiency, removal, and decomposition rates of collided birds as well as searching for collision victims and recording flight movements and flight reactions towards the powerlines. Annual bird-strike rates and flight phenology were analyzed using generalized additive models (GAMs). We estimated 50.1 collision victims per powerline kilometer per year and demonstrated that pigeons (especially Wood Pigeon, Columba palumbus) accounted for the largest proportion of collision victims (approximately 65%). Our study thus offers the opportunity to estimate the number of bird collisions (and the range of species) that can be expected in areas that are not particularly rich in bird life or sensitive, especially in view of the planned intensive expansion of energy structures in the context of the green energy transition.

Birds doi: 10.3390/birds6010012

Authors: Wafae Squalli Ikram Douini Ismail Mansouri Hamid Achiban Hassane Tahiri Fatima Fadil Michael Wink Mohamed Dakki

Many birds regard partitioning feeding and breeding resources as a strategy to escape competition and co-occurring breeding species. During the breeding season, breeding requirements are essential, yet the patterns and drivers of segregation between and within populations are poorly understood. We monitored the habitat use and chronology of the four co-occurring passerines Eurasian Blackbird, European Greenfinch, Common Chaffinch, and European Serin to examine levels of habitat partitioning and success rates during the breeding season. We recorded nesting sites, nest supports, nest placement, breeding chronology, and productivity in four olive orchards in Fez, central Morocco, from March to August 2018–2019. Our results showed substantial spatial segregation in nesting sites, nest supports, and tree vertical placements. Breeding birds showed significant temporal segregation during the nesting, laying, and hatching phases. These findings suggest distinct spatial and temporal differences in habitat selection among co-occurring passerines, which are suggested to increase avoidance of intra and interspecific competition for resources. Breeding success was very high in European Serin and Eurasian Blackbird. Failure factors were recorded: eggs of European Serin were threatened principally by desertion, abortion, and destruction, and eggs of European Greenfinch were impacted by poaching by children. Our findings provide the first data on the spatial and temporal partitioning of breeding resources among passerines species in Northwest African and probably Mediterranean agroecosystems.

Birds doi: 10.3390/birds6010011

Authors: Bethany L. Ostrom Mary J. Harner Andrew J. Caven

Several researchers have tried to find relationships between acoustic indices and vocal animal communities to use acoustic indices as a passive monitoring method, as human-derived surveys are expensive, time-consuming, and suffer from observer bias. However, supplanting manual surveys with acoustic indices is a daunting task, considering effective indices for biological monitoring need to differentiate biologically relevant sounds from the broader soundscape, including anthropophony and geophony. The objective of our study was to test how well acoustic indices can be applied to avian community monitoring within a temperate grassland ecosystem in North America. We collected avian community data and calculated six commonly used acoustic indices from recordings in an intact lowland tallgrass prairie in the Central Platte River Valley of Nebraska throughout the avian breeding seasons of 2019–2021. Singular acoustic indices had only weak correlations with all community metrics. However, multivariate models including multiple acoustic indices showed potential for monitoring grassland bird abundance when anthropophony was considered. Fragmented grassland remnants likely experience significant anthropophony that needs to be accounted for when monitoring avian populations. Additionally, multivariate models incorporating several indices may provide a more accurate prediction of avian biophony than individual acoustic indices.

Birds doi: 10.3390/birds6010010

Authors: Lara Carrasco Eva Jiménez-Mora Maria J. Utrilla Inés Téllez Pizarro Marina M. Reglero Laura Rico-San Román Barbara Martin-Maldonado

The global crisis of plastic pollution, particularly involving microplastics (MPs) and nanoplastics (NPs), has profound ecological implications. Birds, serving as bioindicators, are especially susceptible to these pollutants. This systematic review synthesizes the current research on the presence, distribution, and impact of MPs and NPs on avian species, alongside advancements in detection methodologies. MPs and NPs have been identified in over 200 bird species across 46 families, encompassing several ecosystems, from Antarctica to Labrador, including Australia, China, and South Europe. Seabirds such as penguins, gulls, and shearwaters exhibit a high burden of MPs in tissues and feces due to fishing debris, while terrestrial species face contamination from urban and agricultural sources. Depending on their composition, MPs can cause gastrointestinal damage, oxidative stress, and bioaccumulation of toxic chemicals, particularly polyethylene and polypropylene. However, challenges in detection persist due to methodological inconsistencies, though advances in spectroscopy and flow cytometry offer improved accuracy. Addressing this pollution is vital for bird conservation and ecosystem health, requiring international collaboration and standardized research protocols.

Birds doi: 10.3390/birds6010009

Authors: Bill A. Thompson

Thresholds can be an effective tool in conservation planning, as they can form a defensible target for habitat conservation or restoration. Generalized thresholds must be used with caution, however, as threshold responses may vary with species and spatial scale. The objectives of this study were to identify the scales at which forest-dwelling birds respond to both habitat availability and critical thresholds in forest cover associated with their occurrence, and to assess if life history traits relate to either scale of response or critical threshold. Using point count data from the Ontario Breeding Bird Atlas, I generated concentric buffers ranging from 100 m to 10 km radius around a random subset of point counts and described forest cover and species occurrence within each buffer. I assessed the likelihood of occurrence of each species at each scale of analysis using logistic regression and identified forest cover thresholds below which the occurrence of each species becomes unlikely using fitted regression curves and ROC plots. Species varied in their response to both landscape scale and forest cover, based on relative growth rate, clutch size, and site fidelity. The mean response to forest cover was 30.8%, with landscape scale ranging from 200 m to 9 km. Despite this range, pragmatic approaches to conservation planning are still possible.

Birds doi: 10.3390/birds6010008

Authors: Catalina B. Muñoz-Pacheco Javiera C. Gutiérrez Nélida R. Villaseñor

Urbanization has drastically transformed natural landscapes, threatening biodiversity by reducing species richness and abundance in cities. In this context, seasonal streams serve as refuge areas for various bird species. To determine the role of seasonal streams in conserving native terrestrial avifauna in Algarrobo, an expanding urban environment, we compared bird diversity in ephemeral streams (n = 18) and residential areas (n = 18). Bird counts were conducted during summer and winter. We utilized a diversity index and Generalized Linear Mixed Models (GLMMs) to assess the richness and abundance of native terrestrial birds, as well as the abundance of six migratory birds. Additionally, species accumulation curves verified whether most present species had been adequately sampled. Our results revealed that seasonal streams harbored a greater richness of native bird species than residential areas. Endemic species were also recorded in these streams. The cumulative number of bird species was higher in the seasonal stream environment compared to residential areas. During winter, a higher abundance of migratory birds (Green-backed Firecrown and Gray-hooded Sierra Finch) was observed in seasonal streams. These findings suggest that seasonal streams play a crucial role in conserving native and migratory birds. Thus, protecting and managing these habitats is essential for maintaining avian biodiversity in urbanized areas.

Birds doi: 10.3390/birds6010007

Authors: Alicia Navarro-Sempere Magdalena García Raúl Cobo Sandra Pascual-García Yolanda Segovia

The retinal structure is generally conserved across vertebrates; however, variations occur due to the relationship between environmental factors and visual perception. Birds have adapted to diverse ecological contexts, evolving specialized visual characteristics. In this study, we examined the retina of Audouin’s Gull (Larus audouinii) using light and transmission electron microscopy. This species is particularly intriguing as it is considered an outlier within the Laridae family: despite being a diurnal bird, it exhibits nocturnal/crepuscular foraging behaviour. Our analysis revealed a retina well adapted for diurnal activity, with features such as a retinal thickness comparable to that of other diurnal birds, a well-developed retinal pigment epithelium, and a high cone-to-rod density ratio. However, we also observed characteristics aligned with nocturnal or crepuscular activity, including a slightly increased rod density in central regions and the presence of two distinct types of horizontal cells in the inner nuclear layer. Additionally, the inner retina showed evidence of complex visual processing. These findings suggest that Audouin’s Gull is an excellent model for visual ecology studies due to its specialized adaptations.

Birds doi: 10.3390/birds6010006

Authors: Anastasios Bounas Nikos Tsiopelas Angelos Evangelidis Christos Barboutis

Timing and spatial distribution patterns of migratory birds are crucial for their conservation, particularly in Greece, which serves as a vital migratory corridor between Europe, Asia, and Africa. Traditional monitoring methods face challenges due to resource limitations and the country’s complex geography. This study aimed to determine the migration phenology and spatial distribution of 18 species of raptors and soaring birds in Greece using citizen science data from eBird, analyzed with generalized additive models (GAMs). We processed 15,940 checklists for spring migration and 9131 for autumn migration from 2010 to 2023. GAMs successfully modeled the migration phenology for most species, revealing variable peak migration dates in spring and more synchronized migration in autumn, with most species migrating in early September. A spatial analysis highlighted the importance of coastal areas and islands (particularly the Aegean islands and Crete) as key migratory routes and stopover sites. Validation with standardized counts from the Antikythira Bird Observatory showed some discrepancies, emphasizing the limitations of relying on a single monitoring site and the value of broad-scale citizen science data. Our findings demonstrate the effectiveness of integrating citizen science data with robust analytical techniques to fill knowledge gaps, providing valuable insights for designing monitoring programs and informing conservation strategies.

Birds doi: 10.3390/birds6010005

Authors: Kaajial Durgapersad Andreas Beutel Nishal Mahatho

Bird streamer faults occur when the streamer, i.e., bird excretion, bridges the gap between two energized components or an energized and an earthed component of a tower structure. This results in a short circuit, which may be accompanied by an outage in the electricity supply. Due to the impact of these faults on electrical infrastructure and bird mortality, a detailed literature review to identify effective mitigation measures for sub-transmission lines (44–132 kV) and transmission lines (132–765 kV) was conducted. The findings show that there are several measures used internationally to reduce streamer-related faults, e.g., bird perch deterrents, shields, changing tower design configurations, changing insulator types and properties, and bird runways. Bird perch deterrents are typically most effectively used by many utilities; however, it is imperative that the perch deterrents are placed and installed correctly. Placement should be above potential problematic areas—to prevent the bridging of the gaps—at various points on different tower structures. Moreover, bird guards need to be monitored and maintained to ensure effectiveness over time. The involvement of a range of stakeholders when making environmental management decisions, such as researching and implementing the best mitigation measures, is also critical to ensure continued success.

Birds doi: 10.3390/birds6010004

Authors: Vegard Sandøy Bråthen Dagfinn Breivik Skomsø Claus Bech

The ratio of the innate heterophils to the acquired lymphocytes (the H/L-ratio) has been advocated as a good indicator of physiological stress. Little is known, however, about their development in wild birds. The present study investigates how leucocyte profiles develop in nestlings of a long-lived seabird, the Black-legged Kittiwake (Rissa tridactyla). We counted blood leucocytes in nestlings of about 10 and 25 days of age (n = 23), and in breeding adults around the time of hatching (n = 40) and calculated the H/L-ratio for all three groups. We further investigated if any variation in the leucocyte counts could be explained by body condition or the stress-related hormone corticosterone. 10-day-old nestlings in better body condition showed greater investment in heterophils, which increased their H/L-ratio. The initial focus on innate immunity shifted towards acquired immunity by 25 days, aligning their H/L-ratio with that of adults. In adult Kittiwakes, however, better body condition correlated with lower H/L-ratio, the reverse of the pattern in young nestlings, and this variation was not linked to stress hormone (corticosterone) levels. Overall, our findings suggest that the H/L-ratio reflects the ontogeny of physiological traits and individual condition. As an indicator, values must be interpreted depending on age, in which its sensitivity may also vary. As such, the H/L-ratio may not always be a reliable indicator of physiological stress, in particular related to the release of glucocorticoid hormones.

Birds doi: 10.3390/birds6010003

Authors: Filipa Loureiro João R. Mesquita Luís Cardoso Cristina Pintado Sara Gomes-Gonçalves Ana C. Matos Vanessa Soeiro Andreia Gonçalves Filipe Silva Manuela Matos Ana Cláudia Coelho

Coxiella burnetii is a highly infectious zoonotic pathogenic bacterium that has a major economic impact in the livestock industry throughout the world and causes unpredictable outbreaks in humans worldwide. Although it is known that birds are potential reservoirs of C. burnetii, their role in the epidemiological cycle of the pathogen has not been fully verified. Due to its non-specific symptoms and clinical signs, it is certainly an underdiagnosed disease. The objective of this study was to obtain more information on C. burnetii prevalence in wild birds in Portugal. Blood, plasma, and other tissue samples were obtained from wild birds admitted at wildlife rehabilitation centres in Portugal in the scope of passive surveillance. Antibodies specific to C. burnetii were screened using a commercial enzyme-linked immunosorbent assay according to the manufacturer’s instructions. Evidence of C. burnetii infection was sought based on the detection of bacterial DNA. No positive results were found, either in terms of antibodies to C. burnetii or molecular biology. These serological findings do not indicate the endemic circulation of C. burnetii in wild birds, which can be considered relevant information. However, a more complete and serialized approach over time is necessary to be able to make real inferences about the endemicity of the pathogen in the country and its dispersion among wild avian populations. qPCR results were also negative, a finding suggesting that this host population may not play a significant role in the transmission dynamics of C. burnetii. Given the importance of wild bird species as natural reservoirs of this zoonotic bacterium, we consider these data useful for multidisciplinary work in the prevention and control of Q fever, following a One Health approach.

Birds doi: 10.3390/birds6010002

Authors: Nico Arcilla Benjamín Salazar Samecash Oscar Tsamajain Shiwig Shan Su Robert J. Cooper

Western Amazonia hosts the highest bird diversity in the world, yet in many regional indigenous territories, biodiversity remains poorly known to science. Between 2004 and 2020, we conducted research with members of 10 indigenous Aguaruna communities in four regions of the northern Peruvian Amazon, recording a total of 427 bird species, including eight wintering Nearctic migratory species. Past studies suggested that unique Aguaruna names exist for the majority of bird species present, and this hypothesis was a focus of our research. We identified unique Aguaruna names for ~38% (161) of bird species documented and generic (shared) Aguaruna names for an additional ~31% (132) of bird species documented; the remaining ~31% (134) of bird species documented had no known Aguaruna name. Avian family membership was a significant predictor of whether a bird species had a unique Aguaruna name. Avian families in which a majority of species had unique Aguaruna names included parrots (Psittacidae), manakins (Pipridae), and nightjars (Caprimulgidae), comprising many conspicuous species in terms of their appearance, vocalizations, and/or behavior. Avian families in which a majority of species had no Aguaruna name included ovenbirds and woodcreepers (Furnariidae), tyrant flycatchers (Tyrannidae), and hummingbirds (Trochilidae), comprising many small, cryptic, forest interior species. Collaborative research on avian ecology together with studies of indigenous names and knowledge offers a basis on which to increase conservation engagement with indigenous people.

Birds doi: 10.3390/birds6010001

Authors: Erica H. Craig Jim D. Herriges Tim H. Craig

We conducted a helicopter survey in 2010 for cliff-nesting raptors along the Dalton Highway in northern Alaska. The study area extended from the Yukon River northward ~395 km through the Brooks Range to the Arctic Plain. We documented 55 occupied raptor nesting territories, including 25 Golden Eagle (Aquila chrysaetos), 11 Gyrfalcon (Falco rusticolus), and 10 Peregrine Falcon (Falco peregrinus) territories. We also recorded vacant stick nests and raptor perch sites on cliffs. We identified more occupied eagle territories and hundreds more vacant eagle stick nests than were previously known in the study area. The average number of Golden Eagle nestlings/nesting pairs at the time of the survey was 1.5 ± 0.6. The most productive Golden Eagle pairs were located in the northern part of the study area. The number of occupied eagle territories in 2010 is far fewer than the number of eagle stick nests we recorded. Our data indicate that the distribution of nesting eagles in the 2010 study area is different than in the past. Whether this reflects changes in eagle density; a response to availability of prey, climate change, human activities, or a combination of these; or some other factor warrants further investigation. Intensive surveys along the Dalton Highway in the 1970s found no occupied nests for Peregrine Falcons or Gyrfalcons but we found 10 and 11, respectively. Therefore, the Peregrine Falcon and Gyrfalcon nests we recorded in 2010 reflect an increase in the number of known nesting pairs there.

Birds doi: 10.3390/birds5040056

Authors: Anastasia Perodaskalaki Stavros Xirouchakis

In the life history of avian taxa, homeothermy, egg laying and the need for rapid growth of the offspring are regarded as crucial evolutionary drivers for their social structure and the establishment of reproductive units [...]

Birds doi: 10.3390/birds5040055

Authors: Sara Morollón Simon Lee Vicente Urios

The Hen Harrier (Circus cyaneus) is a medium-sized raptor with a broad distribution across the Palearctic. In Spain, Hen Harrier behaviour is diverse due to being at the southern limit of its distribution, and the margins of distributions tend to show greater variability in the strategies and behaviours of animals. This study focused on juvenile dispersal, using GPS/GSM data from seven individuals to define movement patterns, compare variables between sexes, and analyse differences between the first and second years of dispersal. To analyse the movements during each annual period, six variables were considered, namely the mean distance from nest location, maximum distance from nest location, mean daily distance travelled, total distance travelled, 95% weekly kernel, and 95% total kernel. In their first year after leaving the nest, the Hen Harriers began dispersal movements on 21 August ± 34.41 days, with highly variable distances and durations among individuals. They travelled an average total of 6774.66 ± 5360.46 km over the two first years, with some significant differences between sexes and periods in terms of movement patterns, particularly in the daily and total distances travelled. Overall, the maximum distance from nest location and the total distance travelled were greater in the first year of dispersal than in the second year, indicating, as expected, an improved understanding of their environment and more efficient movements. The juvenile dispersal behaviour of the Hen Harrier is highly variable and represents the most vulnerable season for survival as the birds navigate new and unexplored territories.

Birds doi: 10.3390/birds5040054

Authors: Lourdes Galiano Carlos M. Leveau Lucas M. Leveau

Urbanization is related to the loss of biodiversity and alteration of ecosystem processes. However, long-term changes in the southern hemisphere’s bird communities have been scarcely analyzed in urban areas. The general objective of this work was to analyze changes in bird species richness, diversity, and composition in parks located in the urban and suburban landscapes of Mar del Plata City (Argentina) between 2003 and 2018. Additionally, we aimed to analyze whether these changes were associated with an increase in urbanization or with alterations in the parks’ habitat structure. Tree cover showed significantly lower coverage during 2018. The results showed increased species richness and diversity in all parks by 2018. Rarefaction curves showed that the park bird richness did not differ between the landscapes surrounding parks, but the Shannon and Simpson diversities were higher in parks in suburban landscapes than in parks in urban landscapes. The Shannon and Simpson diversities showed higher values in suburban parks during 2018. However, the diversity values were similar between years in parks in urban landscapes. The species composition was significantly different between landscapes and years. Species turnover was the most predominant pattern of species dissimilarity between landscapes, and species nestedness explained the most dissimilarity between years. Nestedness between years was related to the population increase in many bird species in 2018. In conclusion, we observed differences in the park bird communities between years and landscape types. However, the long-term community changes were not associated with an urbanization increase. Instead, the changes in the local bird community were more related to regional bird species population changes associated with climate warming and increased crop cover.

Birds doi: 10.3390/birds5040053

Authors: Vagner Cavarzere

Protected areas (PAs) are widely recognized as being essential for maintaining global biodiversity. In this study, I aimed to determine whether PAs support a greater richness of forest bird species than unprotected habitats and whether they exhibit functional diversity indices and traits comparable to those found in protected forests in the eastern Brazilian Semideciduous Atlantic Forest. I conducted bird surveys across 20 forest fragments of varying sizes (43 to 37,000 ha), 12 of which were legally designated as PAs. The results indicated that species richness was not significantly higher in PAs and that there were no significant differences in functional diversity indices and traits between unprotected and protected forests. In eastern Brazil, some forest remnants were designated as PAs merely because they were among the last remaining patches within a heavily fragmented landscape. Therefore, protected areas do not necessarily serve as accurate proxies for well-preserved habitats.

Birds doi: 10.3390/birds5040052

Authors: Omar Maya-García Elisa Maya-Elizarrarás Carlos Lara Jorge E. Schondube

Arthropods are hummingbirds’ principal source of nitrogen, fatty acids, and micronutrients. Despite the nutritional importance of arthropods for hummingbirds, our understanding of the factors influencing their consumption and their relative role as an energy source remains limited. Here, we aimed to describe the use of arthropods by a hummingbird ensemble in a seasonal temperate mountain ecosystem in West Mexico during one annual cycle. We compared arthropod capture attempt rates among six different humming species. Also, we investigated the impact of seasonal variation in food availability on the arthropod capture attempt rates of the White-eared Hummingbird (Basilinna leucotis), the sole species observed foraging for arthropods in all seasons. We found that hummingbirds ingested arthropods from different orders (Araneae, Hemiptera, Psocoptera, Hymenoptera, and Diptera), with arthropod capture attempt rates varying wildly among species. The arthropod capture attempt rates of the White-eared Hummingbird showed a significant positive correlation with arthropod availability, peaking during the warm-dry season when floral nectar was scarce and arthropod availability was high. Our data show that arthropod ingestion is crucial for some hummingbird species, mainly when nectar availability is limited or absent in the environment.

Birds doi: 10.3390/birds5040051

Authors: Daiana N. Lera Natalia Cozzani Julia L. Camina José L. Tella Sergio Zalba

Data on the interactions between the order Psittaciformes and the anthropogenic environment are still insufficient and have not been systematized, especially in the Neotropical region. As a consequence of this coexistence, the volume of accumulated knowledge is probably significantly greater than the formal scientific contributions on the subject. In this survey, information was compiled on the wild parrots inhabiting cities in the Southern Cone of South America, based on surveys with key informants. The results obtained highlighted the presence of a large number of parrot species that form part of the urban avifauna of the region, between 67% and 90% of the total number of species of the order cited for each territory evaluated. The greatest species richness and the number of breeding species were associated with the large cities located in middle and low latitudes. We confirmed breeding within the cities for more than 40% of the species mentioned. Seventy-five percent of the species reported are native to the study area, the rest originating from other regions of South America or other continents. A quarter of the reported species are considered threatened and almost 50% have declining populations. Urban parrots represent a challenge in the search for urban models compatible with biodiversity conservation, and in the designing of innovative conservation strategies that respond to the new challenges posed by a constantly growing human population.