Accumulation of Parabens, Their Metabolites, and Halogenated Byproducts in Migratory Birds of Prey: A Comparative Study in Texas and North Carolina, USA.

Parabens are alkyl esters of p-hydroxybenzoic acid that are commonly used as preservatives in personal care products such as cosmetics. Recent studies have revealed the presence of parabens in surface and tap water because of their use as disinfection products; however, little is known about their occurrence in biological samples and their bioaccumulation potential, particularly in raptor birds known as sentinels for pollutant detection. We examined the occurrence and tissue distribution of parabens, their metabolites, and halogenated byproducts in the liver, kidney, brain, and muscle of birds of prey from Texas and North Carolina (USA). Methylparaben (MeP), propylparaben (PrP), and butylparaben (BuP) were detected in more than 50% of all tissues examined, with the kidney exhibiting the highest concentration of MeP (0.65-6.84 ng/g wet wt). Para-hydroxybenzoic acid (PHBA), a primary metabolite, had the highest detection frequency (>50%) and a high accumulation range in the liver, of 4.64 to 12.55 ng/g. The chlorinated compounds chloromethylparaben and chloroethylparaben were found in over half of the tissues, of which dichloromethylparaben (2.20-3.99 ng/g) and dichloroethylparaben (1.01-5.95 ng/g) in the kidney exhibited the highest concentrations. The dibrominated derivatives dibromideethylparaben (Br2EtP) was detected in more than 50% of samples, particularly in muscle and brain. Concentrations in the range of 0.14 to 17.38 ng/g of Br2EtP were detected in the kidney. Dibromidepropylparaben (Br2PrP) was not frequently detected, but concentrations ranged from 0.09 to 21.70 ng/g in muscle. The accumulations of total amounts (sum) of parent parabens (∑P), metabolites (∑M), and halogenated byproducts (∑H) in different species were not significantly different, but their distribution in tissues differed among the species. Positive correlations were observed among MeP, PrP, BuP, and PHBA in the liver, suggesting similar origins and metabolic pathways. Environ Toxicol Chem 2024;43:2365-2376. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Bill shape variation in selected species in birds of prey.

At the top of many ecosystems, raptors, also known as birds of prey, hold major influence. They shape their surroundings through their powerful hunting skills and complex interactions with their environment. This study investigates the beak morphology of four prominent raptor species, Golden eagle (Aquila chrysaetos), Common buzzard (Buteo buteo), Peregrine falcon (Falco peregrinus) and Common kestrel (Falco tinnunculus), found in Türkiye. By employing geometric morphometric methods, we investigate shape variations in the beaks of these species to unravel the adaptive significance of their cranial structures. This analysis reveals distinct beak morphologies among the studied raptors, reflecting adaptations to their feeding habits, hunting techniques and ecological niches. The results from Principal component analysis and Canonical variate analysis demonstrate significant differences in beak morphology between the Falconiformes and Accipitriformes clades, as well as among all three groups. The overall mean beak shapes of Golden Eagles are quite similar to Common Buzzards, with both species having longer beaks. In contrast, Falcons exhibit a distinctly different beak morphology, characterized by wider and shorter beaks. Changes in beak shape can lead to changes depending on the skull. It is thought that skull shape variations among predator families may have an impact on beak shape. These findings highlight the importance of integrating morphometric analyses with ecological insights to enhance our understanding of the evolutionary processes shaping raptor beak morphology.

Pharmaceuticals in avian scavengers and other birds of prey: A toxicological perspective to improve risk assessments.

Pharmaceuticals are emerging contaminants given their increasing use worldwide due to intensive food production and population growth. These compounds reach the environment through different pathways with potential negative consequences for wildlife. One dramatic example occurred in Asia, where three native vulture populations collapsed almost to extinction due to acute intoxication with diclofenac, a veterinary use non-steroidal anti-inflammatory drug (NSAID). As seen with diclofenac, avian scavengers are useful sentinels to monitor for the presence of pharmaceuticals in the environment given their position at the top of the trophic chain, and in the case of obligate avian scavengers (vultures), their intimate link to domestic animal carcasses. Unfortunately, little is known about the wider exposure and potential health and population risks of pharmaceuticals to birds of prey. Here we compile literature data regarding relevant toxicological aspects of the most important pharmaceutical groups for birds of prey in terms of toxicity: NSAIDs, antibiotics, external antiparasitics and barbiturates. This work also includes critical information for future risk assessments, including concentrations of drug residues that can remain in animal tissues after treatment, or specific pharmaceutical features that might influence their toxicity in avian scavengers and other birds of prey. We also consider future research needs in this field and provide management recommendations to prevent potential intoxication events with pharmaceuticals in these species. This review highlights the need to consider specific risk assessments regarding exposure to pharmaceuticals, especially those used in veterinary medicine, for birds of prey.

Continental scale dietary patterns in a New World raptor using web-sourced photographs.

Dietary studies are essential to better understand raptor ecology and resource requirements through time and space, informing species habitat use, interspecific interactions and demographic rates. Methods used to collect data on raptor diets can constrain how dietary analyses can be interpreted. Traditional approaches to study raptor diets, such as analysis of pellets or prey remains, often provide dietary data at the local population level and tend to be restricted to pairs during the breeding season. The increasing use of citizen science data has the potential to provide dietary inferences at larger spatial, demographic and temporal scales. Using web-sourced photography, we explore continental-scale demographic and latitudinal dietary patterns between adult and non-adult Crested Caracaras (Caracara plancus), throughout the species' range across the Americas. We analysed 1,555 photographs of caracaras feeding and found no age effects on the probabilities of different food groups being included in photographs. The probability of reptiles being included in photographs of caracaras from the northern population was significantly higher than those from the southern population, with the opposite pattern for birds. There were significant latitudinal effects with the probabilities of fishes and invertebrates in the diet of northern caracaras increasing towards the equator. Contrastingly, the probability of mammals in the diet increased away from the equator for both populations. Assuming the focal species is well-sampled, web-sourced photography can improve our understanding of raptor diets at large-scales and complements more traditional approaches. This approach is more accessible to raptor researchers without access to the field or expertise in physical prey identification techniques.

Presence of micronuclei and nuclear abnormalities in Caracara (Polyborus) plancus living in an airport area in southern Brazil.

The aviation sector is believed to be responsible for considerable environmental damage attributed to emission of a large number and amount of pollutants. Airports are often surrounded by forest fragments and humid areas that attract birds of prey and hence may potentially serve as useful bioindicators. The aim of the present study was to examine genotoxic potential in raptors exposed to airport pollution using the micronucleus (MN) test and morphological changes as evidenced by bilateral symmetry. This investigation was conducted at Salgado Filho International Airport of Porto Alegre - RS as well as in private and zoological breeding grounds. The presence of metals was measured in the blood cells of the collected birds. Seventeen birds (Caracara (Polyborus) plancus) were used in this study 11 from exposed and 6 from non-exposed group. The nuclear alterations clearly indicate that organisms exposed to airport pollution exhibited a significantly higher frequency of genetic damage compared to non-exposed birds. Further, manganese and chromium were detected exclusively in the blood of the exposed group. In contrast, the analysis of bilateral symmetry did not detect any significant morphologic differences between the two groups. Therefore, data indicate that blood genotoxic stress occurs in birds of prey living in civil aviation areas as evidenced by MN frequency increase and presence of manganese and chromium.

Lead poisoning of raptors: state of the science and cross-discipline mitigation options for a global problem.

Lead poisoning is an important global conservation problem for many species of wildlife, especially raptors. Despite the increasing number of individual studies and regional reviews of lead poisoning of raptors, it has been over a decade since this information has been compiled into a comprehensive global review. Here, we summarize the state of knowledge of lead poisoning of raptors, we review developments in manufacturing of non-lead ammunition, the use of which can reduce the most pervasive source of lead these birds encounter, and we compile data on voluntary and regulatory mitigation options and their associated sociological context. We support our literature review with case studies of mitigation actions, largely provided by the conservation practitioners who study or manage these efforts. Our review illustrates the growing awareness and understanding of lead exposure of raptors, and it shows that the science underpinning this understanding has expanded considerably in recent years. We also show that the political and social appetite for managing lead ammunition appears to vary substantially across administrative regions, countries, and continents. Improved understanding of the drivers of this variation could support more effective mitigation of lead exposure of wildlife. This review also shows that mitigation strategies are likely to be most effective when they are outcome driven, consider behavioural theory, local cultures, and environmental conditions, effectively monitor participation, compliance, and levels of raptor exposure, and support both environmental and human health.

Current situation of lead (Pb) exposure in raptors and waterfowl in Japan and difference in sensitivity to in vitro lead exposure among avian species.

Although lead (Pb) poisoning in wild birds has been considered a serious problem in Japan for over 30 years, there is little information about Pb exposure and its sources throughout Japan except for Hokkaido. Furthermore, to identify and effectively prioritize the conservation needs of highly vulnerable species, differences in sensitivity to Pb exposure among avian species need to be determined. Therefore, we investigated the current situation of Pb exposure in raptors (13 species, N = 82), waterfowl (eight species, N = 44) and crows (one species, N = 6) using concentration and isotope analysis. We employed blood or tissue samples collected in various Japanese facilities mainly in 2022 or 2023. We also carried out a comparative study of blood δ-ALAD sensitivity to in vitro Pb exposure using blood of nine avian species. Pb concentrations in the blood or tissues displayed increased levels (>0.1 µg/g blood) in two raptors (2.4%), ten waterfowl (23%) and one crow (17%). Among them, poisoning levels (>0.6 µg/g blood) were found in one black kite and one common teal. The sources of Pb isotope ratios in ten blood samples with high Pb levels were determined as deriving from shot pellets (N = 9) or rifle bullets (N = 1). In the δ-ALAD study, red-crowned crane showed the highest sensitivity among the nine tested avian species and was followed in order by five Accipitriformes species (including white-tailed and Steller's sea eagle), Blakiston's fish owl, Muscovy duck and chicken, suggesting a genetically driven variance in susceptibility. Further studies on contamination conditions and exposure sources are urgently needed to inform strict regulations on the usage of Pb ammunition. Furthermore, detailed examinations of δ-ALAD sensitivity, interspecific differences, and other factors involved in the variability in sensitivity to Pb are required to identify and prioritize highly sensitive species.

Shoulder viscoelasticity in a raptor-inspired model alleviates instability and enhances passive gust rejection.

Recent experiments with gliding raptors reveal a perplexing dichotomy: remarkably resilient gust rejection, but, at the same time, an exceptionally high degree of longitudinal instability. To resolve this incompatibility, a multiple degree of freedom model is developed with minimal requisite complexity to examine the hypothesis that the bird shoulder joint may embed essential stabilizing and preflexive mechanisms for rejecting rapid perturbations while simplifying and reducing control effort. Thus, the formulation herein is centrally premised upon distinct wing pitch and body pitch angles coupled via a Kelvin-Voigt viscoelastic shoulder joint. The model accurately exhibits empirical gust response of an unstable gliding raptor, generates biologically plausible equilibrium configurations, and the viscoelastic shoulder coupling is shown to drastically alleviate the high degree of instability predicted by conventional linear flight dynamics models. In fact, stability analysis of the model predicts a critical system timescale (the time to double amplitude of a pitch divergence mode) that is commensurate within vivomeasured latency of barn owls (Tyto alba). Active gust mitigation is studied by presupposing the owl behaves as an optimal controller. The system is under-actuated and the feedback control law is resolved in the controllable subspace using a Kalman decomposition. Importantly, control-theoretic analysis precisely identifies what discrete gust frequencies may be rapidly and passively rejected versus disturbances requiring feedback control intervention.

Quantitative analysis of the morphing wing mechanism of raptors: Bionic design of Falco Peregrinus wing skeleton.

The wing is one of the most important parts of a bird's locomotor system and is the inspiration origination for bionic wing design. During wing motions, the wing shape is closely related to the rotation angles of wing bones. Therefore, the research on the law of bone movement in the process of wing movement can be good guidance for the design of the bionic morphing wing. In this paper, the skeletal posture of the peregrine falcon wing during the extension/flexion is studied to obtain critical data on skeletal posture. Since an elbow joint and a wrist joint rotate correlatively to drive a wing to flex/extend, the wing skeleton is simplified as a four-bar mechanism in this paper. The degree of reproduction of wing skeleton postures was quantitatively analyzed using the four-bar mechanism model, and the bionic wing skeleton was designed. It is found that the wing motions have been reproduced with high precision.

Surveillance for highly pathogenic avian influenza A (H5N1) in a raptor rehabilitation center-2022.

An ongoing, severe outbreak of highly pathogenic avian influenza virus (HPAI) A H5N1 clade 2.3.4.4b has been circulating in wild and domestic bird populations throughout the world, reaching North America in 2021. This HPAI outbreak has exhibited unique characteristics when compared to previous outbreaks. The global distribution of disease, prolonged duration, extensive number of species and individual wild birds affected, and the large impact on the global poultry industry have all exceeded historical impacts of previous outbreaks in North America. In this study, we describe the results of HPAI surveillance conducted at The Raptor Center, a wildlife rehabilitation hospital at University of Minnesota (Saint Paul, MN, U.S.A.), from March 28th-December 31, 2022. All wild raptors admitted to the facility were tested for avian influenza viruses using polymerase chain reaction (PCR) testing. All non-negative samples were submitted to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories for confirmatory HPAI testing and genetic sequencing. During the study period, 996 individual birds representing 20 different species were tested for avian influenza, and 213 birds were confirmed HPAI positive. Highly pathogenic avian influenza surveillance conducted at The Raptor Center contributed 75% of the HPAI positive raptor detections within the state of Minnesota, located within the Mississippi flyway, significantly augmenting state wildlife surveillance efforts. The viral genotypes observed in birds sampled at The Raptor Center were representative of what was seen in wild bird surveillance within the Mississippi flyway during the same time frame. Wildlife rehabilitation centers provide an opportune situation to augment disease surveillance at the human, wildlife and domestic animal interface during ongoing infectious disease outbreaks.

Quantitative evaluation of the global impacts of human land modification on raptors.

Raptors are threatened by anthropogenic land modifications, but targeted quantitative assessment of these impacts is lacking. We conducted the first global quantitative evaluation of the impacts of human-modified land on raptors. We used eBird data from 2001 to 2020 on 425 raptor species and occupancy models to assess the impacts of human-modified land on raptor distribution. The mean spatiotemporal correlations of human settlement, cropland, and pasture with raptor occupancy probability were -0.048 (SE 0.031), -0.134 (0.032), and -0.145 (0.032), respectively. The mean sensitivity of raptor occupancy probability to settlement, cropland, and pasture was -5.760 (2.266), -3.128 (1.540), and -2.402 (1.551), respectively. The occupancy probability of raptors with a large body mass was more negatively correlated with cropland (phylogenetic generalized least squares regressions: slope = -0.052 [SE 0.022], t = -2.335, df = 1, 407, p = 0.020, λ = 0.006) and more positively correlated with pasture (slope = 0.047 [0.022], t = 2.118, df = 1, 407, p = 0.035, λ = 0.013). The occupancy probability of raptors with a more extensive range size was more positively correlated with cropland (slope = 0.002 [0.004], t = 0.399, df = 1, 407, p < 0.001, λ = 0.000). Raptors that prefer open habitats were more positively correlated with cropland (analysis of variance: F = 3.424, df = 2, p = 0.034, λ = 0.000) and pasture (F = 6.577, df = 2, p = 0.002, λ = 0.000). In Africa and South America, where raptor species are most abundant, raptor occupancy probability decreased over 20 years, most likely due to habitat fragmentation associated with human land modification. Although raptors with different ecological characteristics had different responses to human land modification, the impacts of settlement, cropland, and pasture on mean raptor occupancy probability were negative, regardless of space and time.

Evaluación cuantitativa del impacto global de la modificación humana del uso de suelo sobre las rapaces Resumen Las rapaces se encuentran amenazadas por las modificaciones de suelo antropogénicas, pero la evaluación cuantitativa focalizada de estos impactos es muy escasa. Realizamos la primera evaluación cuantitativa mundial del impacto del suelo modificado por humanos sobre las rapaces. Usamos datos de eBird desde 2001 hasta 2020 sobre 425 especies rapaces y modelos de ocupación para evaluar el impacto del suelo modificado por humanos sobre la distribución de estas especies. La correlación espaciotemporal media de los asentamientos humanos, las tierras de cultivo y las pasturas con probabilidad de ocupación por rapaces fueron ­0,048 (SE 0,031), ­0,134 (0,032) y ­0,145 (0,032), respectivamente. La sensibilidad media de la probabilidad de ocupación de las rapaces a los asentamientos, las tierras de cultivo y las pasturas fue de ­5,760 (2,266), ­3,128 (1,540) y ­2,402 (1,551), respectivamente. La probabilidad de ocupación de las rapaces con gran masa corporal tuvo una correlación más negativa con las tierras de cultivo (regresiones filogenéticas por mínimos cuadrados generalizados: pendiente =­0. 052 [SE 0,022], t = ­2,335, gl = 1, 407, p = 0,020, λ = 0,006) y una correlación más positiva con los pastos (pendiente = 0,047 [0,022], t = 2,118, gl = 1, 407, p = 0,035, λ = 0,013). La probabilidad de ocupación de las rapaces con un área de distribución más extensa tuvo una correlación más positiva con las tierras de cultivo (pendiente = 0,002 [0,004], t = 0,399, gl = 1, 407, p < 0,001, λ = 0,000). Las rapaces que prefieren hábitats abiertos tuvieron una correlación más positiva con las tierras de cultivo (análisis de la varianza: F = 3,424, gl = 2, p = 0,034, λ = 0,000) y los pastos (F = 6,577, df = 2, p = 0,002, λ = 0,000). En África y América del Sur, en donde son más abundantes las especies rapaces, la probabilidad de ocupación de las rapaces disminuyó a lo largo de 20 años, probablemente debido a la fragmentación de hábitat asociada con la modificación del suelo por humanos. Aunque las rapaces con características ecológicas diferentes tienen diferentes respuestas a estas modificaciones, el impacto de los asentamientos, las tierras de cultivo y las pasturas fue negativo para la probabilidad de ocupación media de las rapaces, sin importar el espacio ni el tiempo.

Comprehensive text for raptor enthusiasts.

Reviewed by Thomas Dutton, an RCVS-recognised Specialist in avian medicine.

Anticoagulant Rodenticide Toxicity in Terrestrial Raptors: Tools to Estimate the Impact on Populations in North America and Globally.

Anticoagulant rodenticides (ARs) have caused widespread contamination and poisoning of predators and scavengers. The diagnosis of toxicity proceeds from evidence of hemorrhage, and subsequent detection of residues in liver. Many factors confound the assessment of AR poisoning, particularly exposure dose, timing and frequency of exposure, and individual and taxon-specific variables. There is a need, therefore, for better AR toxicity criteria. To respond, we compiled a database of second-generation anticoagulant rodenticide (SGAR) residues in liver and postmortem evaluations of 951 terrestrial raptor carcasses from Canada and the United States, 1989 to 2021. We developed mixed-effects logistic regression models to produce specific probability curves of the toxicity of ∑SGARs at the taxonomic level of the family, and separately for three SGARs registered in North America, brodifacoum, bromadiolone, and difethialone. The ∑SGAR threshold concentrations for diagnosis of coagulopathy at 0.20 probability of risk were highest for strigid owls (15 ng g-1) lower and relatively similar for accipitrid hawks and eagles (8.2 ng g-1) and falcons (7.9 ng g-1), and much lower for tytonid barn owls (0.32 ng g-1). These values are lower than those we found previously, due to compilation and use of a larger database with a mix of species and source locations, and also to refinements in the statistical methods. Our presentation of results on the family taxonomic level should aid in the global applicability of the numbers. We also collated a subset of 440 single-compound exposure events and determined the probability of SGAR-poisoning symptoms as a function of SGAR concentration, which we then used to estimate relative SGAR toxicity and toxic equivalence factors: difethialone, 1, brodifacoum, 0.8, and bromadiolone, 0.5. Environ Toxicol Chem 2024;43:988-998. © 2024 His Majesty the King in Right of Canada and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Novel phylogenetic clade of avian Haemoproteus parasites (Haemosporida, Haemoproteidae) from Accipitridae raptors, with description of a new Haemoproteus species.

Avian haemosporidian parasites (order Haemosporida, phylum Apicomplexa) are blood and tissue parasites transmitted by blood-sucking dipteran insects. Three genera (Plasmodium, Haemoproteus and Leucocytozoon) have been most often found in birds, with over 270 species described and named in avian hosts based mainly on the morphological characters of blood stages. A broad diversity of Haemoproteus parasites remains to be identified and characterized morphologically and molecularly, especially those infecting birds of prey, an underrepresented bird group in haemosporidian parasite studies. The aim of this study was to investigate and identify Haemoproteus parasites from a large sample comprising accipitriform raptors of 16 species combining morphological and new molecular protocols targeting the cytb genes of this parasite group. This study provides morphological descriptions and molecular characterizations of two Haemoproteus species, H. multivacuolatus n. sp. and H. nisi Peirce and Marquiss, 1983. Haemoproteus parasites of this group were so far found in accipitriform raptors only and might be classified into a separate subgenus or even genus. Cytb sequences of these parasites diverge by more than 15% from those of all others known avian haemosporidian genera and form a unique phylogenetic clade. This study underlines the importance of developing new diagnostic tools to detect molecularly highly divergent parasites that might be undetectable by commonly used conventional tools.

Title: Nouveau clade phylogénétique de parasites de rapaces Accipitridae du genre Haemoproteus (Haemosporida, Haemoproteidae), avec description d'une nouvelle espèce d'Haemoproteus. Abstract: Les parasites hémosporidies aviaires (ordre Haemosporida, phylum Apicomplexa) sont des parasites sanguins et tissulaires transmis par des insectes diptères hématophages. Trois genres (Plasmodium, Haemoproteus et Leucocytozoon) ont été le plus souvent trouvés chez les oiseaux, avec plus de 270 espèces décrites et nommées chez les hôtes aviaires en fonction principalement des caractères morphologiques des stades sanguins. Une grande diversité des Haemoproteus reste à identifier et à caractériser morphologiquement et génétiquement, en particulier ceux qui infectent les oiseaux de proie, un groupe d'oiseaux sous-représenté dans les études sur les hémosporidies. Le but de cette étude était d'étudier et d'identifier les Haemoproteus à partir d'un large échantillon comprenant des rapaces accipitriformes de 16 espèces, en combinant des protocoles morphologiques et de nouveaux protocoles moléculaires ciblant les gènes cytb de ce groupe de parasites. Cette étude fournit des descriptions morphologiques et des caractérisations moléculaires de deux espèces d'Haemoproteus, H. multivacuolatus n. sp. et H. nisi Peirce and Marquiss, 1983. Les Haemoproteus de ce groupe n'ont jusqu'à présent été trouvés que chez les rapaces accipitriformes et pourraient être classés dans un sous-genre ou même un genre distinct. Les séquences cytb de ces parasites divergent de plus de 15 % de celles de tous les autres genres d'hémosporidies aviaires connus et forment un clade phylogénétique unique. Cette étude souligne l'importance de développer de nouveaux outils de diagnostic pour détecter des parasites moléculairement très divergents qui pourraient être indétectables par les outils conventionnels couramment utilisés.

New Insights on the Male and Female Reproductive Organs of Centrorhynchus globocaudatus (Acanthocephala), Intestinal Parasite of Birds of Prey.

Acanthocephalans are dioecious parasites that gain sexual maturity in the alimentary canal of their definitive hosts (gnathostome vertebrates). This initial survey by light and transmission electron microscopy was conducted on the functional organization of the ovarian balls and uterine bell in mature females and on Saefftigen's pouch and the copulatory bursa in males. We studied these structures via the example of Centrorhynchus globocaudatus (Palaeacanthocephala) in Falco tinnunculus and Buteo buteo, from the Province of Ferrara (Northern Italy). Our study confirms that the ovarian balls have surface microvilli and consist of a multinucleate supporting syncytium and a cellular region with oogonial syncytium, single germ cells, zygotes, and shelled eggs. Germ cells are embedded in the supporting syncytium. The ultrastructural features of these components and data on fertilization, shell formation, and release from the ovarian ball, alongside insights into the likely egg sorting function of the uterine bell, are provided. We also present light and electron microscopy observations of Saefftigen's pouch and a suggestion regarding its hydrostatic functioning in the eversion of the copulatory bursa.

African savanna raptors show evidence of widespread population collapse and a growing dependence on protected areas.

The conversion of natural habitats to farmland is a major cause of biodiversity loss and poses the greatest extinction risk to birds worldwide. Tropical raptors are of particular concern, being relatively slow-breeding apex predators and scavengers, whose disappearance can trigger extensive cascading effects. Many of Africa's raptors are at considerable risk from habitat conversion, prey-base depletion and persecution, driven principally by human population expansion. Here we describe multiregional trends among 42 African raptor species, 88% of which have declined over a ca. 20-40-yr period, with 69% exceeding the International Union for Conservation of Nature criteria classifying species at risk of extinction. Large raptors had experienced significantly steeper declines than smaller species, and this disparity was more pronounced on unprotected land. Declines were greater in West Africa than elsewhere, and more than twice as severe outside of protected areas (PAs) than within. Worryingly, species suffering the steepest declines had become significantly more dependent on PAs, demonstrating the importance of expanding conservation areas to cover 30% of land by 2030-a key target agreed at the UN Convention on Biological Diversity COP15. Our findings also highlight the significance of a recent African-led proposal to strengthen PA management-initiatives considered fundamental to safeguarding global biodiversity, ecosystem functioning and climate resilience.

Stereoselective bioaccumulation of chiral anticoagulant rodenticides in the liver of predatory and scavenging raptors.

Second-generation anticoagulant rodenticides (SGARs) are persistent chiral pesticides used to control rodent populations. Raptors are protected species and may be exposed through the ingestion of rodents contaminated with SGARs. Commercial formulations of SGARs are a mixture of four stereoisomers (E1, E2, E3, E4): the cis- and trans-diastereoisomers are each a racemic mixture of two enantiomers. In this study, the residue levels of all SGARs (bromadiolone, difenacoum, brodifacoum, difethialone, flocoumafen) were evaluated in the liver of 529 raptor carcasses. All species (n = 18) and 75 % of individuals (n = 396) were SGAR positive and 29 % (n = 154) had summed hepatic concentrations above 100 ng/g ww. Concentrations were higher for predators with facultative scavenging behaviors than for predators and obligate scavengers. Bromadiolone, brodifacoum and difenacoum had equivalent hepatic prevalence (between 48.9 and 49.9 %), and difethialone was detected less frequently (31.7 %). Concentrations and enantiomeric fractions of the four stereoisomers of all SGARs are described in to demonstrate the biological enantioselectivity of these chiral pesticides in the food chain. A difference was observed between the proportions of SGARs diastereoisomers and stereoisomers in the liver of all raptor species and in commercial baits. The enantioselective bioaccumulation of E1-trans-bromadiolone, E3-cis-brodifacoum, E1-cis-difenacoum and E3-cis-difethialone was characterized and represented 96.8 % of total SGARs hepatic residues. While hepatic concentrations were heterogeneous, the proportions of stereoisomers and diastereoisomers were homogeneous with no inter-individual or inter-species differences (only E1-trans-bromadiolone is present in hepatic residues). However, proportions of brodifacoum stereoisomers and diastereoisomers were more scattered, probably due to their slower elimination. This could provide an opportunity to date the exposure of individuals to brodifacoum. We highlight the need to consider each SGAR as four molecular entities (four stereoisomers) rather than one. These findings suggest new commercial formulations with the less persistent stereoisomers could reduce secondary exposure of non-target species.

Evaluation of anticoagulant rodenticide sensitivity by examining in vivo and in vitro responses in avian species, focusing on raptors.

Anticoagulant rodenticides (ARs) are used to control pest rodent species but can result in secondary poisoning of non-target animals, especially raptors. In the present study, differences in AR sensitivity among avian species were evaluated by comparing in vivo warfarin pharmacokinetics and effects, measuring cytochrome P450s (CYPs) expression involved in AR metabolism, and conducting in vitro inhibition assays of the AR target enzyme Vitamin K 2,3-epoxide reductase (VKOR). Oral administration of warfarin at 4 mg/kg body weight did not prolong prothrombin time in chickens (Gallus gallus), rock pigeons (Columba livia), or Eastern buzzards (Buteo japonicus). Rock pigeons and buzzards exhibited shorter plasma half-life of warfarin compared to chickens. For the metabolite analysis, 4'-hydroxywarfarin was predominantly detected in all birds, while 10-hydroxywarfarin was only found in pigeons and raptors, indicating interspecific differences in AR metabolism among birds likely due to differential expression of CYP enzymes involved in the metabolism of ARs and variation of VKOR activities among these avian species. The present findings, and results of our earlier investigations, demonstrate pronounced differences in AR sensitivity and pharmacokinetics among bird species, and in particular raptors. While ecological risk assessment and mitigation efforts for ARs have been extensive, AR exposure and adverse effects in predatory and scavenging wildlife continues. Toxicokinetic and toxicodynamic data will assist in such risk assessments and mitigation efforts.

Surveillance for Avian Bornavirus in Colorado and Wyoming, USA, Raptor Populations.

Avian bornavirus (ABV) is known to infect at least 80 avian species and is associated with avian bornaviral ganglioneuritis (ABG). Avian bornaviral ganglioneuritis is characterized by a lymphoplasmacytic infiltration of the nervous tissue, mainly affecting the nerves that supply the gastrointestinal tract of birds. This disease is diagnosed commonly in psittacines under human care and has been demonstrated in wild bird species; however, its occurrence in raptors is largely unknown. Because of the commonality of ABV in the pet bird population, there is concern about the spread of this virus to other companion avian species, such as falconry birds, as well as wildlife. This prospective study used reverse-transcription quantitative PCR (RT-qPCR) to survey free-ranging Colorado and Wyoming, US, raptor populations for ABV. Quantitative PCR was performed on mixed conjunctival-choanal-cloacal swabs collected from live birds (n=139). In dead birds, a combination of mixed swabs (n=265) and tissue samples of the brain (n=258), heart (n=162), adrenal glands (n=162), liver (n=162), kidney (n=139), spinal cord (n=139), and brachial plexus (n=139) were evaluated. All 1,565 swab and tissue samples RT-qPCR results from the 404 birds evaluated were negative. Based on these results and a lack of clinical signs suggestive of ABG, ABV is likely not a prevalent pathogen in Colorado and Wyoming raptor populations at this time.

Morbidity and Mortality of Birds of Prey Admitted to Rehabilitation Centers for Barbed Wire Injuries, New Mexico, USA, 2016-2021.

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.