Birds, Volume 7, Issue 1 (March 2026) – 22 articles

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article