Birds

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

Birds select habitats to optimize resources and maximize fitness, with some species recently colonizing new areas, like the Eurasian Collared Dove (ECD) in the Iberian Peninsula. The ECD spread across Europe in the early 20th century from South Asia. This study reanalyzes data from the Atlas of Breeding Birds in the Province of Alicante (SE Spain) to identify macrohabitat-level environmental variables related to its occurrence and abundance in this semi-arid Mediterranean landscape during the breeding season. We performed Hierarchical Partitioning analyses to identify important environmental variables for the species associated with natural vegetation, farming, topography, hydrographical web, urbanization, and climate. Results show that ECD has a higher occurrence probability near anthropic areas (isolated buildings, suburban areas), water points (medium-sized ponds), larger crop surfaces (total cultivated area), and warmer localities (thermicity index). The species avoids natural habitats like pine forests and scrublands. Abundance is positively linked to anthropic features like larger suburban areas and urban-related land uses. These findings can help predict its expansion in regions with a Mediterranean climate in South America, North America, or Australia, and its continuous natural expansion and population increase within the Mediterranean basin and Europe. Full article

Bird populations inhabiting the Rio de la Plata Grasslands in southern Brazil, Argentina, and Uruguay are known to be affected by livestock grazing practices. Cattle grazing can lead to changes in bird assemblages by affecting the heterogeneity of vegetation structures. We conducted a meta-analysis using studies that reported bird richness and abundance under different grazing management practices. We compared ranches under continuous grazing management (control, CGM) to (1) ranches under technological inputs management (TIM, herbicides and exotic pastures) and (2) ranches under ecological process-based management (EPM), which include ranches that utilise controlled and rotational grazing. We used random effects multilevel linear models to evaluate grazing regimen impacts. Our results indicate a negative impact of TIM on both bird abundance and richness (mean ± SE: −0.25 ± 0.07 and −0.92 ± 0.10, respectively) since the use of inputs simplifies vegetation structure and results in the loss of ecological niches. Compared to CGM, the influence of EPM on total bird abundance appears to be more dependent on grassland height, as evidenced by a decline in short grasses and increase in tall grasses. Our meta-analysis suggests that EPM practices may be beneficial for the conservation of endangered tall-grass birds. Full article

The characteristics of building surroundings can influence the number of bird deaths caused by collisions with glass structures. Thus, this study investigated whether the number of trees, the distance to the nearest tree, the number of fruit trees, and the glass area influenced the number of bird collisions on a university campus in Brazil from March 2017 (breeding and non-breeding seasons) to January 2018 (breeding season). Twenty-four birds died due to collisions with the windows in the one-year sampling. Among the factors evaluated, the number of trees and the area of the glass predicted the number of deaths from collisions. The greater the number of trees and the glass area, the greater the number of bird collisions. This suggests that the more vegetation there is near windows, the more birds are attracted, and the less visible the glass barrier becomes, possibly due to the appearance of trees in reflections or scenes viewed through the glass, making it difficult for birds to distinguish the real landscape from the reflected environment. If large expanses of glass are placed on buildings near vegetation, including trees, more bird collisions will occur. Thus, to reduce bird collisions, building designs should reduce the amount of glass used on building exteriors near vegetation and ensure the glass is treated with visual markers. Full article

Little is known about landbird group dynamics in response to predation. Here, we describe the interactions between the Helmeted Guineafowl (Numida meleagris) and its predators regarding the survival advantages grouping behaviour may provide. Livestream webcam observations were conducted in Madikwe Game Reserve (South Africa) from August 2020 to August 2021. Emphasis was placed on predator–prey interaction and its effect on group size and structure in a spatial framework. We hypothesise that while grouping is crucial for a number of daily activities in this highly social species, it might turn into a higher predatory pressure. We found, indeed, that the probability of attacks by black-backed jackals (Lupulella mesomelas) significantly increased with guineafowl group size, unlike what happened with raptors. Moreover, when attacked by jackals, the birds responded by standing close to each other. These results suggest, in line with the proposed hypothesis, that a trade-off occurs between the defensive function of grouping in this galliform and the probability of jackal attack that increases as a function of prey group size. Nevertheless, we argue that Helmeted Guineafowl cooperative social groups also play a role as a defensive strategy against predators, with the many-eyes and dilution effects likely compensating for the higher predatory pressure. Full article

In Poland, it is highly probable that in past centuries, Common Cranes (Grus grus) were widespread all over the country. In the 19th century, a particularly dramatic decline in this population took place when Common Cranes abandoned many regions. At present, this species inhabits the whole of lowland Poland, only avoiding the uplands and mountainous regions in the south of the country. The rate of population growth between 2001 and 2018 was c. 5% per annum. The breeding population increased tenfold in the 30 years from 1990 to 2020. The results of the Polish Bird Monitoring Programme in 2018–2020 show that Common Crane numbers had stabilized. The latest count (2013–2018) of breeding pairs in Poland is 23,000–30,000, while that for the years 2010–2012 was 20,000–22,000, i.e., 15% of the European population or 19% of the breeding population in the EU. The greatest threats to the Polish Common Crane population come from habitat and climate changes, two factors that are inextricably interlinked. Experts are alerting that climate warming, in combination with increased pressure from human activities, can, in the long term, reverse this trend and lead to declines in Common Crane populations in this part of Europe. Full article

Non-native species have caused various problems for both animal and human communities globally, but their monitoring during the early stages of establishment is often difficult. A population of the Oriental Magpie (Pica serica) has established on Hokkaido Island, northern Japan, since the 1990s, offering a rare opportunity for field biologists to monitor the entire history of a colonizing avian population. To clarify the current number and distribution of the population and their major determinants, we conducted bimonthly surveys from May 2012 to March 2013, over a total of 417 h, in Tomakomai City, the central area of the current distribution. We found 181 to 248 magpies in every survey, and 46 active nests in May. Most of the magpies appeared in residential areas, avoiding commercial and industrial areas, and did not show seasonal changes in their distribution pattern. The magpies mainly foraged in short grasslands in public spaces, such as parks, in May and July, but most of the birds preferred house gardens for foraging from November to March. Dogs or cats were often kept outside in the gardens where the magpies foraged, and observations of magpies stealing and hoarding pet food were common. It is likely that the magpies rely on anthropogenic food resources such as pet food, especially in winter. Continuous monitoring of this population will enable further knowledge of the factors that limit the number and range of not only non-native species but also avian populations in general to be obtained. Full article

The phenomenon of interspecies brood parasitism, characterized by parasitic birds depositing their eggs within the nests of unrelated host species for subsequent hatching and rearing, represents a pivotal aspect of ornithological research, owing to its profound implications for the coevolutionary dynamics between host and parasite species. Among the myriad of avian brood parasites, the Common Cuckoo (Cuculus canorus) stands out due to its expansive geographical range and diverse array of host species, thereby underscoring its significance in the context of parasitism studies. Drawing upon historical records dating back to the Three Kingdoms period (220–280 AD) in China, this study delves into the annals of avian brood parasitism, uncovering instances of parasitic behavior attributed to the Common Cuckoo. Through a meticulous analysis of these ancient narratives, coupled with an examination of the ecological and morphological attributes of the birds involved, we confirm the parasitization of Barn Swallows (Hirundo rustica) by Common Cuckoos. This finding underscores the existence of a long-standing coevolutionary relationship between these two species, extending over nearly two millennia. Remarkably, the record under scrutiny, with its precise temporal, geographical, and taxonomic specifications, emerges as a potential candidate for the earliest documented instance of Common Cuckoo brood parasitism in Chinese historical records. As such, it provides invaluable insights into the historical ecology of avian parasitism and underscores the need for further interdisciplinary research to unravel the complexities of host–parasite interactions across time and space. Full article

In wildlife rehabilitation centers, thousands of animals are treated annually, with a substantial proportion being birds of prey. Since vision is essential for the survival of these species, this study focused on investigating the causes of ocular injuries in raptors admitted to four rehabilitation centers across mainland Portugal from 2017 to 2021. Of the 2207 birds admitted during this period, 156 (7%) presented ocular injuries. Hyphema (28.2%) and corneal ulcers (20.5%) were the most prevalent injuries, often occurring together or alongside lens luxation. Nocturnal raptors showed a higher prevalence of these injuries (76.9%) compared to diurnal raptors (23.1%). A significant association was found between ocular injuries and causes of admission, particularly with ocular hemorrhages and multiple injuries in the eye. Despite the severity of the ocular injuries, the release rate remained relatively high at 51%, underscoring the critical role of comprehensive ocular examinations and vision assessments in guiding treatment decisions and discharge decisions. This study highlights the need for further research with larger samples to better understand the impact of ocular injuries on the rehabilitation success of wild birds in Portugal. Full article

Forest fires are disturbance events that can impact biological assemblages at multiple scales. In this study, the structures of breeding bird communities in cork oak patches located in an agro-mosaic suburban landscape of central Italy (Rome) were compared at the local scale with a fine-grained mapping method before (2018) and after (2023) a fire event occurred in July 2022. The analyses did not reveal any significant changes in the density of territorial pairs or in the diversity metrics, both univariate (Shannon–Wiener index, evenness, Margalef normalized richness) and bivariate (Whittaker and k-dominance plots, abundance/biomass curves) of diversity. Even when the guilds of strictly forest-related species were compared, no differences emerged before and after the fire. This counterintuitive phenomenon may be due to the characteristics of the dominant tree, the cork oak (Quercus suber), a sclerophilous tree that is very resilient to fires and able to recover foliage in the following spring season, thus allowing rapid bird recolonization. However, other small-scale phenomena (e.g., the ‘crowding effect’ and local dispersal of territorial pairs from remnant wood patches not affected by fire) may explain this lack of change in breeding bird density and diversity. Further studies should be carried out at larger spatial and temporal scales and at different levels of fire frequency and intensity to confirm these responses at the guild/community level in suburban cork oak wood patches. Full article

Electrical faults caused by power escaping electric systems can lead to power outages, equipment damage, and fires. Faults sometimes occur when birds perched on power structures are electrocuted. Distribution power lines supported by concrete and steel pylons are particularly fault-prone because small separations between conductors and grounded components allow even small birds to inadvertently create faults while being electrocuted. Most conservation solutions focus on covering energized wires and components to prevent contact by birds and, although usually effective when installed correctly, covers can sometimes be dislodged thus becoming ineffective. Glass Flake Epoxy (GFE) is a non-conductive thermoset plastic that can adhere to steel crossarms and not be dislodged. We hypothesized that GFE-coated crossarms might reduce faults (proxies for avian electrocutions), and we conducted laboratory and field trials to evaluate that hypothesis. In the laboratory, we found a 2000 micrometer (μm)-thick layer of GFE coating that created a dielectric strength of 12.30 ± 0.21 kV, which was sufficient to prevent the formation of a phase-to-ground fault on up to 20 kV distribution lines. This should allow birds to perch on metal crossarms without being electrocuted. In field trials, we substituted 24% of a 20 kV distribution pylon’s crossarms with GFE-treated crossarms and found that doing so correlated with a 28% decrease in faults. Although we did not measure avian electrocutions directly, our findings suggest GFE coatings may offer a novel method of reducing avian electrocutions on power lines. Full article

Haemosporidians are common blood parasites in wild bird populations, yet their effects on oxidative status remain understudied. Here, we measured the levels of thiobarbituric acid-reactive substances (TBARS) as an indicator of reactive oxygen species (ROS), total antioxidant capacity (TAC) as an indicator of non-enzymatic molecular antioxidants, and TBARS/TAC ratio as an indicator of oxidative status. We also used parasite genus-specific primers and PCR techniques to detect haemosporidians in 117 adults of Rufous-collared Sparrow (Zonotrichia capensis) from four locations in south–central Chile. Mixed-effect models were employed to compare oxidative indicators between infected and uninfected birds. Infected birds showed significantly higher TBARS levels, but no significant differences in TAC, leading to a higher TBARS/TAC ratio, especially in reproductive individuals. This suggests increased oxidative damage in infected birds, irrespective of sex or body condition. A positive relationship between TBARS and TAC was observed in both groups, but the antioxidant response was weaker in infected birds, indicating differential oxidative stress responses based on infection status. Body condition did not differ significantly between infected and uninfected individuals. These results demonstrate that haemosporidian infections impose oxidative costs on birds, potentially compounding the oxidative costs associated with reproduction. Full article

Zoo enclosure design, and housing and husbandry protocols, will always be a compromise between what a species has evolved to do and what is possible to offer in a human-created environment. For some species, behaviours that are commonly performed in the wild may be constrained by husbandry practices that are used for ease or aesthetics or are accepted conventions. As zoos place more emphasis on positive animal welfare states, zoo enclosures should be scrutinised to check that what is provided, in terms of useful space, appropriate replication of habitat features, and maximal potential for natural behaviour performance, is relevant to the species and individuals being housed. For some species, zoos need to grapple with tough questions where the answer may not seem immediately obvious to ensure they are continuously improving standards of care, opportunities for the performance of species-typical behaviours, and advancing the attainment of positive welfare states. Determining the importance of flight, for example, and what this behaviour adds to the quality of life of a zoo-housed bird, is an important question that needs addressing to truly advance aviculture and how we determine bird welfare. This paper provides questions that should be answered and poses measures of what flight means to a bird, to provide evidence for the development and evolution of zoo bird housing. If we can devise some way of asking the animals in our care what they need, we can more firmly support decisions made that surround enclosure design, and housing decisions. Ultimately, this means gathering evidence on whether birds like to fly (e.g., from birds in training or demonstration activities) by applying mixed methods approaches of behavioural analysis, data on wild ecology, qualitative behavioural assessment, and cognitive bias testing to develop a robust suite of tools to address avian welfare considerations. Avian welfare scientists should attempt to define what meaningful flight is (i.e., flight that truly suggests a bird is flying) in order to support guidelines on aviary dimensions, space allowance, and welfare outputs from birds in both flighted and flight-restricted populations, and to determine what is most appropriate for an individual species. Changing the term “best practice” husbandry guidelines to “better practice” husbandry guidelines would instil the importance of regular review and reassessment of housing and management suitability for a species to ensure such care regimes remain appropriate. With an increasingly welfare-savvy public visiting zoos, it is essential that we seek more evidence to support and justify how birds are kept and ultimately use such evidence to enact changes to practices that are shown to infringe on avian welfare. Full article

In the present study, 7344 spring observations of a short-distance migratory species, the Eurasian Woodcock, from the Carpathian Basin between 1894 and 1926 were used to investigate the timing of the species’ migration and how different environmental factors influenced it. We used a generalized additive model (GAM) to explore migratory patterns by using environmental and geographical variables. In years when the weather was colder and snowier, the birds migrated weeks later than in years with milder weather. This may be due to the availability of earthworms, which are the most important food for the species. In areas at lower altitudes, migration occurred earlier than in mountainous areas, which may also be due to the different weather. Furthermore, a two week difference was observed between the south-western and north-eastern parts of the Carpathian Basin. This difference is still present nowadays, but the timing of migration has shifted earlier than in the past, probably due to climate change. It would also be important to compare the historical data with recent data to gain a better understanding of the effects of climate change on the migration of the Eurasian Woodcock. Full article

Raptors usually show use for a particular habitat to settle during the breeding period. In this study, we aimed to study the habitat use of the breeding populations of Hen Harrier (Circus cyaneus) in Spain, which represents the southern distribution limit of the species. We used GPS/GSM data from 17 individuals during 21 breeding periods. We analysed space and habitat use using 95% kernel density estimators to obtain home ranges during the breeding period. Then, we performed a third-order habitat selection analysis, extracting the percentage of locations on each land use and comparing it with random points generated within each home range. Furthermore, an Agricultural Use Index was created to classify harriers with agricultural or forest use depending on habitat. The results showed that harriers had a general use for agricultural land and, to a lesser extent, habitats with natural vegetation scrubs. Nest location was key to habitat selection, and these uses varied with latitude, with natural vegetation being chosen as the nesting habitat in the north and agricultural fields in the south, probably due to the availability of habitats in different parts of Iberia. Full article