Birds

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

Migratory birds play an important role in the spread of yeasts in the environment over long distances and in different geographical regions. Human activities, in turn, have a major impact on the biology of wild birds and, consequently, on the microbial communities for which birds act as carriers and disseminators. We sought to assess the “response” of the diversity of culturable yeasts in the feces of Mew Gulls to the type of nesting site (natural/anthropogenic) during the breeding season from April to October 2023. We isolated and molecularly identified 26 yeast species. The species composition in the feces of birds from the natural habitat was more diverse, and the diversity increased from April to October. In contrast, the diversity in the feces of birds from the urban habitat decreased from April to October. Analysis of susceptibility to conventional antibiotics (fluconazole, voriconazole, and amphotericin B) using the CLSI BMD (Clinical and Laboratory Standards Institute broth microdilution) method in isolated strains of opportunistic Candida (C. parapsilosis and C. tropicalis) and strains of the emerging pathogen Rhodotorula mucilaginosa showed that the proportion of resistant strains was higher in strains isolated from the feces of birds from the anthropogenic population. Mew Gulls that spent their breeding season near a landfill and flew away for wintering appear to be a source for the spread of pathogenic yeasts with resistance against antifungal agents. Full article

As habitat loss and other threats accelerate, ecological restoration and reintroduction science are becoming progressively more important. The psittacines are among the most endangered bird groups and are prime candidates for restoration through reintroduction. Unfortunately, post-release survival of captive-raised animals is often quite low because, in part, of high predation rates, low site fidelity, poor flight ability, and low flock cohesion. Current best practices in parrot release hold the birds in captivity for a year or more and include distinct methods to address each of these challenges. Here, we conduct a small-scale, proof-of-concept study using free flight methods and human-socialized trained adult birds to hand raise and release a group of six fledgling Blue-and-yellow Macaws in their historical range in southeastern Brazil. All six released birds showed strong flock cohesion and fidelity to the release site, avoided predation, and survived without supplemental feeding for over one year. One bird was captured by local people but was recovered and rereleased and it has reintegrated into the group and is still alive and doing well. The human-socialized trained adult birds modeled both desirable behaviors (flocking, foraging, reacting to predators) and undesirable behaviors and they were returned to captivity before the conclusion of this study. Our study suggests that free flight training has great potential to help captive-raised young attain a broad array of vital skills needed for survival post-release. Full article

The Mexican duck (Anas diazi) is an endemic species that has been categorized as threatened because of its practice of living in small populations and because of the condition of the wetlands in which it occurs. Therefore, the preference for wetlands by the species is influenced by the adjacent vegetation composition found in the Mexican Central Plateau in the state of Zacatecas. The inclination of the duck towards the wetlands in relation to the aquatic and adjacent vegetation structure was evaluated in the studied area. Seven wetlands were selected and distinguished by the presence of a population of the species. Vegetation was analyzed in three strata—tree layer, shrub layer and herb layer—and the population of the Mexican duck was calculated through direct counting in each wetland. The results determined a significantly larger number of individuals in artificial wetlands than in lakes. The wetlands’ adjacent vegetation is constituted by graminean and shrub species, with an aquatic vegetation cover. The non-parametric Mann–Whitney U test showed a significant difference between the counts of ducks and the physical structure of wetlands in the examined area. The data obtained indicate that the Mexican Duck occurs mainly in artificial wetlands with mainly graminean vegetation and aquatic plant cover; similar characteristics to those previously described for dabbling ducks. Full article

Single individuals of the Greater Spotted Eagle (Clanga clanga), Indian Spotted Eagle (Clanga hastata), Tawny Eagle (Aquila rapax), Western Marsh Harrier (Circus aeruginosus), and two Pallid Harriers (Circus macrourus) were deployed with satellite transmitters in 2021 to study their home ranges, habitat associations, movement, and migration patterns. Data were collected for a combined number of 2291 days, providing 84,544 locations. Home ranges were calculated as kernel utilization distributions and expressed as 95% KDE and core areas as 50% KDE. Overall, eagles had larger home ranges (mean ± SD) of 942.70 ± 937.83 km² compared to harriers, 43.84 ± 35.55 km². Among eagles, the Greater Spotted Eagle had the largest home-range size of 2147.03 km² calculated in Kazakhstan, while the female Pallid Harrier had the smallest home range of 5.74 km² in Russia. Daily and monthly distances varied among eagles and harriers. The female Pallid Harrier covered the longest average monthly distance of 8585.43 ± 11,943.39 km, while the shortest monthly distance of 1338.22 ± 716.38 km was traveled by the Indian Spotted Eagle. All tagged birds migrated toward higher latitudes in the Northern hemisphere, except the Indian Spotted Eagle, which migrated to Pakistan. The male Western Marsh Harrier covered the longest migration distance in a shorter span of time, while the female Pallid Harrier took the longest to cover its migration distance. Overall, the daily distance covered during migration varied from 115.09 km traveled by the Indian Spotted Eagle to an overwhelming distance of 2035.85 km covered by the male Western Marsh Harrier. Scrubs, water bodies, croplands, and settlements were important habitat features associated with eagles, while croplands, open scrub, and built-up areas were associated with the female Pallid Harrier. The male Western Marsh Harrier was found to be primarily associated with saltpans and salt-affected areas having emergent vegetation. This study presents new insights into the movement and spatial ecology of long-distance migrant raptors that winter in Western India. We provide preliminary support for the use of the Western Circum–Himalayan Corridor as one of the important corridors of the Central Asian Flyway that warrants much appreciation among the current set of flyway corridors. Full article

Despite high-quality insect food being often restricted in cities, insects are important for the development of birds. Nonetheless, plenty of insects are smashed on cars, and they are available for those species that are able to use them. We used both our own data and community science and Internet sources for surveying global, national, and local data about birds using insects on cars. Our results contained a total of 308 observations of birds collecting insects on car panels, which indicated that 39 species used this food resource since 1928 in 33 countries. Most observations considered the House Sparrow, followed by the White Wagtail and several species of corvids. European urban bird species observed to use insects on cars had a larger residual brain size. There was also some indication that bird species using insects on cars had a larger number of innovations (i.e., production of novel behaviors), greater diet generalism, and longer times living in urbanized areas than birds not observed using insects on cars. Often these species are also resident and able to use food offered in feeding sites. We assume that more bird species will use insects on cars in the future, as urban insect populations continue to decline, and thereby insects on cars will increasingly become more important sources of food for urban birds. Full article

In the Galapagos Islands, the main road in Santa Cruz is one of the elements involved in bird road mortality along with vehicles and the impacted species. This study reports the number of roadkilled birds found on the road from the Itabaca Channel to Puerto Ayora, and the main factors, whether avian or environmental, involved in bird roadkill mortality. We collected individual carcasses in 2004, 2005, 2006, and 2018 with a prevalence of 278, 252, 265, and 294, respectively, across 21 species. The endemic Yellow Warbler Setophaga petechia aureola was the most affected bird. We used a PRIDIT model to rank the top avian and environmental predictors of road mortality. We found that for the sampled years, bird body size (i.e., 8–35 g) and the endemism status (i.e., endemic/native) were the main predictors of roadkill mortality, along with seasonality (i.e., hot season). Weaker predictors related to the bird (i.e., age and sex) and the environment (ecosystem, road slope, vegetation, or precipitation) are also reported as determinants of roadkill mortality. This study on avian mortality aims to inform conservation strategies to reduce the rate of wildlife avian roadkill on Santa Cruz Island and other islands with similar problems. Full article

Abandoned mine drainage treatment ponds could have contrasting effects on the reproductive success of birds living in the vicinity. The ponds and associated vegetation may, like any other body of freshwater, provide beneficial habitats for the insects that the birds use to feed their young; or instead, the ponds may act as an ecological trap, attracting the birds to a habitat that is poor in quality and negatively impacting their productivity. We monitored nests of an aerial insectivore, the Tree Swallow (Tachycineta bicolor), to determine whether the distance between the ponds and the nests affected various reproductive parameters including clutch size, hatch rate, number of nestlings, nestling size and mass, number of fledglings, fledging rate, and fledge date. Data were collected over two breeding seasons (2022 and 2023) from a swallow population in southwestern Pennsylvania, USA. We found that the nests closest to the treatment ponds had significantly more nestlings and fledglings, earlier fledge dates, and a better fledging rate when compared to nests that were more distant from the ponds. However, all these parameters were well below previously published values, which suggests that the mine drainage ponds provide good nesting habitats relative to what is available in the region but that they do not represent high-quality habitats for this species overall. Full article