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Research Highlight: Bourbour et al., 2024. Feeding en route: Prey availability and traits influence prey selection by an avian predator on migration. Journal of Animal Ecology. Diet selection plays a key role in the eco-evolutionary dynamics of animals, exhibiting substantial variability across species, environments and seasons. The complex interplay between movement capability, hunting strategies, habitat use, prey traits and availability shapes the foraging patterns of avian predators. However, detailed information on how these birds exploit their extensive territories remains limited. In this study, Bourbour et al. utilised a novel integration of eDNA metabarcoding and citizen science to explore predator-prey interactions between migrating sharp-shinned hawks (Accipiter striatus) and an ephemeral avian prey community along North America's Pacific flyway. The research identified 1396 detections from the diet (65 species) of 588 migrating sharp-shinned hawks. Hawks' diet composition correlated with prey abundance indices sourced from the eBird database throughout the migration season, highlighting the significant impact of prey availability-shaped by migration tendency, flocking behaviour, and habitat-on raptor-songbird interactions. Notably, the study also found significant differences in prey size between male and female hawks, indicating that sexual dimorphism has led to diverse foraging strategies during migration. These findings underscore the potential of combining eDNA metabarcoding with citizen science to deepen our understanding of the foraging ecology of highly mobile and wide-ranging birds, as well as to monitor complex and vast ecosystems.

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Interest in the role of fences in wildlife movement and injuries is growing, especially in the western US, where many miles of barbed wire fences crisscross the landscape. However, literature is limited on the effect of barbed wire on avian populations. From 2016 to 2021, six New Mexico, USA, rehabilitation centers accepted 49 raptors injured by barbed wire. Eight species were represented; the majority were Great Horned Owls (Bubo virginianus). Other owls, buteos, and a single falcon were also affected. Most of the injured birds came from counties with low human population density. The injuries tended to be severe, and most birds died or were euthanized; 11 survived, and only eight birds were released. During the study period, barbed wire injuries accounted for over 12% of Great-horned Owl admissions to rehabilitation centers and 7% of all owl admissions. At one New Mexican wildlife rehabilitation center, raptors admitted for barbed wire-associated injuries were more likely to die or be euthanized compared with those admitted for other reasons. Given the welfare effects to these birds, more research is needed to determine whether wildlife-friendly fence modifications, such as a smooth top wire or rail, would mitigate injuries to birds of prey.

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Abstract The American Barn Owl (Tyto furcata) lives in urban, periurban and wild environments and feeds mainly on small rodents, meaning it has great importance in the biological control of pests. The aim of this work was to describe the reproductive, parental and eating habits of a pair of American barn owls naturally living outside a residence in the urban area of the municipality of Campos dos Goytacazes, Rio de Janeiro state, Brazil. A wood box was installed on an outside wall of the home, monitored by a video camera. A spreadsheet was created to keep track of the observations recorded. The female laid four eggs, and after an incubation period of 30-32 days all the eggs hatched, but only two chicks survived after cannibalism among the chicks. Initially, the male provided the food to the chicks and the female remained in the nest caring for the brood. After approximately a month, the female also began to leave the nest and return with prey, which was offered to the chicks, with the male also continuing this behavior. The chicks left the nest in September, 2017. The data obtained show the existence of cooperation and division of tasks between male and female owls during the reproductive period.

Resumo A coruja-das-torres americana (Tyto furcata) vive em ambientes urbanos e se alimenta principalmente de pequenos roedores, sendo de grande importância no controle biológico de pragas. O objetivo deste trabalho foi descrever os hábitos alimentares, parentais e reprodutivos de um casal de corujas-das-torres americanas, naturalmente vivendo fora de uma residência na zona urbana do município de Campos dos Goytacazes, estado do Rio de Janeiro, Brasil. Uma caixa de madeira foi instalada em uma parede externa da casa, monitorada por uma câmera de vídeo. Uma planilha foi criada para manter o controle das observações registradas. A fêmea pôs quatro ovos, e após período de incubação de 30-32 dias todos os ovos eclodiram, mas apenas dois filhotes sobreviveram após o canibalismo entre os filhotes. Inicialmente, o macho fornecia a comida aos filhotes e a fêmea permanecia no ninho cuidando da ninhada. Depois de cerca de um mês, a fêmea também começou a sair do ninho e voltar com a presa, que era oferecida aos filhotes, com o macho também continuando com esse comportamento. Os filhotes deixaram o ninho em setembro de 2017. Os dados obtidos mostram a existência de cooperação e divisão de tarefas entre corujas machos e fêmeas durante o período reprodutivo.

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Abstract The American Barn Owl (Tyto furcata) lives in urban, periurban and wild environments and feeds mainly on small rodents, meaning it has great importance in the biological control of pests. The aim of this work was to describe the reproductive, parental and eating habits of a pair of American barn owls naturally living outside a residence in the urban area of the municipality of Campos dos Goytacazes, Rio de Janeiro state, Brazil. A wood box was installed on an outside wall of the home, monitored by a video camera. A spreadsheet was created to keep track of the observations recorded. The female laid four eggs, and after an incubation period of 30-32 days all the eggs hatched, but only two chicks survived after cannibalism among the chicks. Initially, the male provided the food to the chicks and the female remained in the nest caring for the brood. After approximately a month, the female also began to leave the nest and return with prey, which was offered to the chicks, with the male also continuing this behavior. The chicks left the nest in September, 2017. The data obtained show the existence of cooperation and division of tasks between male and female owls during the reproductive period.

Resumo A coruja-das-torres americana (Tyto furcata) vive em ambientes urbanos e se alimenta principalmente de pequenos roedores, sendo de grande importância no controle biológico de pragas. O objetivo deste trabalho foi descrever os hábitos alimentares, parentais e reprodutivos de um casal de corujas-das-torres americanas, naturalmente vivendo fora de uma residência na zona urbana do município de Campos dos Goytacazes, estado do Rio de Janeiro, Brasil. Uma caixa de madeira foi instalada em uma parede externa da casa, monitorada por uma câmera de vídeo. Uma planilha foi criada para manter o controle das observações registradas. A fêmea pôs quatro ovos, e após período de incubação de 30-32 dias todos os ovos eclodiram, mas apenas dois filhotes sobreviveram após o canibalismo entre os filhotes. Inicialmente, o macho fornecia a comida aos filhotes e a fêmea permanecia no ninho cuidando da ninhada. Depois de cerca de um mês, a fêmea também começou a sair do ninho e voltar com a presa, que era oferecida aos filhotes, com o macho também continuando com esse comportamento. Os filhotes deixaram o ninho em setembro de 2017. Os dados obtidos mostram a existência de cooperação e divisão de tarefas entre corujas machos e fêmeas durante o período reprodutivo.

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The New World Vultures (Cathartidae) include seven species of obligate scavengers that, despite their ecological relevance, present critical information gaps around their evolutionary history and conservation. Insights into their phylogenetic relationships in recent years has enabled the addressing of such information gaps through approaches based on phylogeny. We reconstructed the ancestral area in America of the current species using two regionalization schemes and methods: Biogeography with Bayesian Evolutionary Analysis (BioGeoBears) and Bayesian Binary Model-Monte Carlo Markov Chains (BBM-MCMC). Then, we identified the priority species and areas for conservation by means of the Evolutionary Distinctiveness index (ED), as a proxy of the uniqueness of species according to phylogeny, and the Global Endangerment index (GE), mapping phylogenetic diversity. We found that the ancestral area of New World Vultures in America corresponds to South America, with dispersal processes that led to a recolonization of North America by Coragyps atratus, Gymnogyps californianus and Cathartes aura. We identified the Black Vulture, G. californianus and Vultur gryphus as priority species based on ED and "Evolutionary Distinct Globally Endangered" (EDGE) indexes, and the lowlands of Amazon River basin and the Orinoco basin and some tributaries areas of the Guiana Shield were identified as the priority areas when mapping the phylogenetic diversity. This study highlights the importance of filling knowledge gaps of species of conservation concern through the integration of evolutionary and ecological information and tools and, thus, developing adequate strategies to enhance the preservation of these species in the face of the current loss of biodiversity.

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BACKGROUND: Electrophoresis can be used to aid in the diagnosis of different diseases in avian species. Capillary zone electrophoresis (CZE) is an automated method that is proposed to be superior to the dye methods used in agarose gel electrophoresis (AGE). However, reference intervals (RIs) for CZE in avian species and comparison studies between electrophoretic methods are lacking. OBJECTIVES: The goals of the current study were to compare AGE and CZE methods and determine reference intervals for CZE using plasma from bald eagles (Haliaeetus leucocephalus). METHODS: Heparinized plasma samples from 44 bald eagles (mean age 18.7 years) under managed care were examined by AGE and CZE. Method comparison analyses were completed, as well as the generation of preliminary RIs using the CZE method and ASVCP guidelines. RESULTS: Passing-Bablok regression and Bland-Altman plots demonstrate that these methods are not equivalent. All fractions were significantly correlated between the methods except for alpha 1 globulin. Inter-assay and intra-assay CVs for CZE were lower or comparable to AGE and ranged from 2.4% to 15.4%, and 0.8% to 8.3%, respectively. CZE resolved more fractions than AGE with two fractions observed in the beta and gamma region vs one for AGE in each region. CONCLUSIONS: CZE provided improved resolution and reproducibility for the quantitation of protein fractions in the bald eagle. Although most fraction results correlated with AGE, these methods were judged as not equivalent, necessitating method-specific Rls. Reference intervals generated from a limited number of mostly aged individuals under managed care should be considered preliminary; additional studies will aid in the production of more robust intervals.

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Brazil is an important wintering area for Falco peregrinus, specifically for the subspecies F. p. tundrius and F. p anatum. Using data from WikiAves, we analyzed and discussed aspects of the species natural history, including migratory behavior, geographical distribution, diet, and ecological interactions. Peregrine Falcons were recorded in the country from October until April. Our data suggest that adults can arrive up to a month earlier than juveniles. Individuals have been recorded in all 26 states and there was no significant difference in their geographical distribution in relation to subspecies or age, but there is an apparent lack of records in the Center of the country. Our results showed that in Brazil peregrines prey mainly on Columbiformes and Charadriiformes. Some individuals share the same perch and engage on agonistic interactions with other bird species, usually mobbing or kleptoparasitism.

O Brasil é uma importante área de invernada para Falco peregrinus, especificamente para as subespécies F. p. tundrius e F. p. anatum. Utilizando dados provenientes do WikiAves, nós analisamos e discutimos aspectos da história natural da espécie, incluindo o comportamento migratório, distribuição geográfica, dieta e interações ecológicas. Os falcões-peregrinos podem ser avistados no país entre outubro e abril. Nossos dados sugerem que adultos chegam até um mês antes dos juvenis. Indivíduos foram registrados em todos os 26 estados e não existe nenhuma diferença significativa na distribuição geográfica devido à subespécie ou faixa etária, mas existe uma aparente escassez na região Centro Oeste. Nossos dados apontam ainda que no Brasil os falcões-peregrinos se alimentam majoritariamente de Columbiformes e Charadriiformes. Alguns indivíduos dividem o mesmo poleiro, registramos também a ocorrência de interações agonísticas com outras espécies, geralmente tumulto ou cleptoparasitismo.

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A 28-year-old male harpy eagle (Harpia harpyja) with a history of anorexia, hyporexia, lethargy, and progressive weight loss was found dead and submitted for post-mortem examination. Gross findings include dark brown discolouration of testes and lungs; the testes were bilaterally enlarged, glistening brown-grey to blackish in appearance, firm, smooth, and multilobulated. The lungs contained a mass with similar features to the testicles, irregularly shaped with multiple nodules. Histology of testis showed round, polygonal and pleomorphic cells, containing melanin pigments and a typical eosinophilic vacuole in their cytoplasm and with severe pleomorphism. An immunohistochemistry panel with Melan-A, vimentin, CK AE1/AE/3, MUM-1 and CD-68 were performed, yielding a positive reaction for Melan-A and vimentin. The morphology of the tumour cells, the presence of melanin pigment and the immunoreactivity for Melan-A and vimentin by the cells led to a diagnosis of rhabdoid melanoma. This is the first case of this pathology in the testis with lung metastasis in a harpy eagle.

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West Nile virus (WNV) is a mosquito-borne Flavivirus that can affect birds, horses, and humans, and is the only zoonotic Flavivirus that has been identified in six continents. In Brazil, until 2010, there was no evidence of WNV circulation. Recently, the virus was isolated from a horse with encephalitis, and the first human cases were registered in Brazil. Despite that, there is still no information on the enzootic cycle of this virus in birds or wildlife. This study aimed to investigate whether there is evidence of WNV circulation among wild birds from Southern Brazil. For this, we used free-living wild raptors (live-trapped or rescued) as potential sentinels to investigate the presence of WNV antibodies using ELISA and plaque reduction neutralization test (PRNT) assay. In addition, the presence of nucleic acids from Flavivirus family members was investigated. None of the birds sampled presented clinical findings compatible with WNV. Of the 200 serum samples from birds of prey belonging to 21 species, ten (5%) were positive for the presence of WNV antibodies on ELISA testing. The PRNT test did not confirm the ELISA results, but indicated that three birds had possibly been exposed to Saint Louis encephalitis virus (SLEV). All samples were negative for Flavivirus RNA. The results presented here evince the need for permanent surveillance for emerging flaviviruses in Brazil, as well as for a contingency policy in the case of human/animal outbreaks, particularly in high-risk areas.

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Background: The bird's beak is a structure in constant growth, covered by keratinized epidermal sheaths called rhamphotheca. When subjected to certain degrees of injury, birds can suffer from lesions and fractures in different parts of the body, including the beak. One can treat simple ranch lesions by antisepsis and covering it with resin while the keratin is replaced; yet in complete fractures, with segment avulsion, they need complex prostheses to restore the functions of the nozzle. The main goal of this study was to report a case of a synthetic rhinotheca prosthesis placement in a wild carcará (Caracara plancus). Case: The carcará was referred to the Veterinary Medical Teaching Hospital of the UNIUBE, at the end of May 2018, by Uberaba's Environmental Police, with a history of having been run over. On the physical examination, the animal showed aggressive behavior, low body weight, increased heart and respiratory rates, mild dehydration and complete fracture of the rhinotheca, with avulsion of the mid-distal portion and presence of necrosis in the remaining proximal remnant, the last one seen after debridement and complete cleansing of the lesion. In the following days, complementary exams were performed aiming a complete evaluation of the animal, these revealed the following: oral cavity swab, positive for Candida sp.; radiography of thoracic and pelvic limbs, without any changes; research of hemoparasites, with a negative result; and complete blood count showing marked leukocytosis. The animal was kept in the hospital's wild animal ward, with a daily handling of 400 g of chicken neck and heart, processed on a blender and was also supplemented with a variety of minerals. After the wild animal was managed for eleven months, evolving to the ideal weight set for the species, the process for making the prosthesis started. At first, the prosthesis was made manually with epoxy resin and polyamide, being molded on the animal's rhinotheca, before that, the carcará was sedated with intranasal midazolam, and then modeled in the ideal shape for the beak. Then, the definitive prosthesis was made with acrylic resin, using the previous mold as a base. The surgical procedure was performed in April 2019, with an anesthetic protocol composed of midazolam, dexmedetomidine, ketamine and morphine for sedation, and maintenance in sevoflurane. Prosthesis and rhinotheca were both fixated by bilateral perforation with a 1.0 mm drill, and later on 2 titanium screws were inserted for dental use, these measuring 1.5 mm. After being correctly threated, the screws received a thin layer of acrylic resin on top, for better fixation. Immediately after the operation, the animal was able to use the prosthesis to feed itself. After the surgical procedure, the bird was destined for a sanctuary, and months later the prosthesis eventually fell. Since then, the bird has remained without it. Discussion: Because the beak did not grow due to trauma and consequent necrosis, and the animal did not adapt well with the remnant still present, the manufacture of the prosthesis was the solution so that it could return to its natural habits and behaviors. For greater adherence and fixation, we opted for the use of 2 titanium screws for dental use with the deposition of a thin layer of acrylic resin on top of both. Prostheses can be successful in fixing, but there are no studies indicating how long they will remain viable. Therefore, even with the success of the procedure, allowing the bird to return to its natural habits and behaviors, until after the fall of the prosthesis, it is an animal that needs to be kept in captivity suitable for daily observation.

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