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 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.

Smaller Australian raptors have greater urban tolerance.

Urbanisation is occurring around the world at a rapid rate and is generally associated with negative impacts on biodiversity at local, regional, and global scales. Examining the behavioural response profiles of wildlife to urbanisation helps differentiate between species that do or do not show adaptive responses to changing landscapes and hence are more or less likely to persist in such environments. Species-specific responses to urbanisation are poorly understood in the Southern Hemisphere compared to the Northern Hemisphere, where most of the published literature is focussed. This is also true for raptors, despite their high diversity and comparably high conservation concern in the Southern Hemisphere, and their critical role within ecosystems as bioindicators of environmental health. Here, we explore this knowledge gap using community science data sourced from eBird to investigate the urban tolerance of 24 Australian raptor species at a continental scale. We integrated eBird data with a global continuous measure of urbanisation, artificial light at night (ALAN), to derive an urban tolerance index, ranking species from positive to negative responses according to their tolerance of urban environments. We then gathered trait data from the published literature to assess whether certain traits (body mass, nest substrate, habitat type, feeding guild, and migratory status) were associated with urban tolerance. Body size was negatively associated with urban tolerance, as smaller raptors had greater urban tolerance than larger raptors. Out of the 24 species analysed, 13 species showed tolerance profiles for urban environments (positive response), and 11 species showed avoidance profiles for urban environments (negative response). The results of this study provide impetus to conserve native habitat and improve urban conditions for larger-bodied raptor species to conserve Australian raptor diversity in an increasingly urbanised world.

Automutilação em abutre real (Sarcoramphus papa) mantido em cativeiro / Automutilation in real vulture (Sarcoramphus papa) maintained in captivity / Automutilación en un buitre dorado (Sarcoramphus papa) mantenido en cautividad

O abutre real (Sarcoramphus papa) é um pássaro compacto de cor extraordinária, cabeça nua, possui carúnculas e papilas carnudas vermelhas e alaranjadas em torno do bico, a íris é branca com um anel orbital vermelho. Em cativeiro, o estresse é uma condição bastante observada, o que pode levar a automutilação, podendo evoluir para lesões graves na pele e músculos. O objetivo do presente relato é descrever os procedimentos adotados em um caso de automutilação em Sarcoramphus papa, mantido em cativeiro, e a importância do manejo adequado para essa espécie em cativeiro. Foi atendido em um Hospital Veterinário Universitário, um urubu-rei apresentando ferimento contaminado, com exposição óssea na asa direita. Após tratamento o animal foi encaminhado para uma reserva conservacionista para que fosse condicionada a voltar para seu habitat natural.(AU)

The real vulture is a compact bird of extraordinary color (in adult plumage). Its bare head, as the scientific name suggests, has caricatures and fleshy red papillae applied around the beak, and an iris of the eye is white with a red orbital ring. In captivity, stress is a widely observed condition, which can lead to self-mutilation, which can progress to severe skin and muscle injuries. The purpose of this report is to describe the procedures adopted in the case of automation in Sarcoramphus papa, kept in captivity and with an importance of the appropriate manual for this species in captivity. He was seen at a University Veterinary Hospital, a king vulture showed a contaminated wound, with bone exposure on the right. After treatment or animal was sent to a conservation reserve to be conditioned and return to its natural habitat.(AU)

buitre real (Sarcoramphus papa) es un ave compacta de extraordinario color, cabeza desnuda, tiene carúnculas y papilas rojas y anaranjadas alrededor del pico, el iris es blanco con un anillo orbital rojo. En cautiverio, el estrés es una condición ampliamente observada, que puede llevar a la automutilación, posiblemente evolucionando en lesiones graves de la piel y los músculos. El objetivo del presente informe es describir los procedimientos adoptados en un caso de automutilación en Sarcoramphus papa, mantenido en cautividad, y la importancia del manejo adecuado para esta especie en cautividad. Un buitre real que presentaba una lesión contaminada con exposición ósea en el ala derecha fue tratado en un Hospital Universitario Veterinario. Tras el tratamiento, el animal fue enviado a una reserva de conservación para que pudiera ser acondicionado para volver a su hábitat natural.(AU)

Web-based citizen science as a tool in conservation research: A case study of prey delivery by the Lesser Spotted Eagle.

Citizen science is increasingly contributing to ecology and conservation research, mostly by the extensive collection of field data. Although webcams attract numerous observers, they have been underused in this respect. We used prey delivery records deposited by citizen scientists in an internet forum linked to webcams to explore the diet composition and food provisioning in a forest-dwelling raptor of conservation concern, the Lesser Spotted Eagle (Clanga pomarina). Four pairs were studied throughout the breeding season. Most of the identified prey items were mammals (62.1%), followed by frogs (31.2%), birds (6.6%) and fish (0.1%). Among mammals, voles accounted for 84.6%, moles 12.1%, water voles 2.4% and weasels 0.4%. Frogs were the most frequently detected prey item in the spring, with a slight increase towards the end of the season, the proportion of mammals increased during the breeding season, and birds were hunted mostly in the middle of the breeding season. However, exact temporal patterns differed between nests. The food delivery rate of males increased over time but decreased somewhat before fledging the young. Females started hunting in mid-summer and their rapidly increasing effort compensated for a reduced male hunting intensity. The data collected by citizen scientists via webcams reflected the general patterns detected in earlier studies, supporting the reliability of crowd-sourced web-based data collection in avian foraging ecology.

A novel survey of raptor collections in Europe and their potential to provide samples for pan-European contaminant monitoring.

This paper provides a novel survey of current collections of frozen raptor carcasses and tissue samples in natural history museums (NHMs), environmental specimen banks (ESBs) and other research collections (ORCs e.g. at universities and research institutes) across Europe and assesses the extent to which collections might support pan-European raptor biomonitoring through the provision of samples for contaminant analyses. The paper is based on questionnaire responses received in late 2018 and early 2019 from 116 institutions. Issues covered include the number of raptor carcasses and diversity of raptor species arriving annually at collections, the number of carcasses stored in freezers, the extent to which collections retain frozen tissue samples, what records are kept of carcasses and tissue samples, constraints to expanding collections of frozen carcasses and tissues and the extent to which collections currently engage in ecotoxicological research and monitoring. Our findings show that collections in Europe receive well over 5000 raptor carcasses per annum, and that NHMs are the key recipients of raptor carcasses for most countries. Collections in Europe probably hold well over 10,000 raptor carcasses in their freezers, offering a substantial resource of frozen raptor carcasses and tissues from recent years. Moreover, these carcasses include good specimen numbers for species that have been prioritized for pan-European contaminant monitoring. Collections are becoming digitized aiding access to samples. However, freezer capacity is a key constraint to retention of carcasses, and contaminant biomonitoring is novel for most NHMs. Our findings on the repository and availability of frozen raptor carcasses and tissues held by collections in Europe can enable greater use of these specimens for pan-European contaminant monitoring in support of better chemicals management. We highlight opportunities to further optimize raptor collections for pan-European contaminant monitoring.

Histomorphometrical study of the tongue epithelium of the peregrine falcon (Falco peregrinus) / Estudo histomorfométrico do epitélio da língua do falcão peregrino (Falco peregrinus)

The aim of this study is to examine the dorsal lingual epithelium of the peregrine falcon (Falco peregrinus) of the family Falconidae. The tongue in its dorsal, lateral and ventral surfaces is covered with a non-keratinized multilayered stratified squamous epithelium. Lamina propria is present beneath the epithelial layers. Morphometrically, thickness of the apex tongue epithelium is more than that in the tongue body. Thickness of the ventral surface of the tongue is less than that in the dorsal one. Thickness of the lateral surface of the tongue was thicker than that in the ventral one and tongue body. Large and small conical papillae appeared on the posterior dorsal surface of the lingual body. There are lingual glands in certain areas of tongue body with numerous openings through the dorsal surface.

O objetivo deste estudo é examinar o epitélio lingual dorsal do falcão peregrino (Falco peregrinus) da família Falconidae. A língua em suas superfícies dorsal, lateral e ventral é coberta por um epitélio escamoso estratificado de múltiplas camadas não queratinizado. A lâmina própria está presente abaixo das camadas epiteliais. Morfometricamente, a espessura do epitélio do ápice da língua é maior do que a do corpo da língua. A espessura da superfície ventral da língua é menor do que a dorsal. A espessura da face lateral da língua foi mais espessa do que na ventral e no corpo da língua. Papilas cônicas grandes e pequenas apareceram na superfície posterior dorsal do corpo lingual. Existem glândulas linguais em certas áreas do corpo da língua com numerosas aberturas na superfície dorsal.

Parental morph combination does not influence innate immune function in nestlings of a colour-polymorphic African raptor.

Conditions experienced during early life can have long-term individual consequences by influencing dispersal, survival, recruitment and productivity. Resource allocation during development can have strong carry-over effects onto these key parameters and is directly determined by the quality of parental care. In the black sparrowhawk (Accipiter melanoleucus), a colour-polymorphic raptor, parental morphs influence nestling somatic growth and survival, with pairs consisting of different colour morphs ('mixed-morph pairs') producing offspring with lower body mass indices, but higher local apparent survival rates. Resource allocation theory could explain this relationship, with nestlings of mixed-morph pairs trading off a more effective innate immune system against somatic growth. We quantified several innate immune parameters of nestlings (hemagglutination, hemolysis, bacteria-killing capacity and haptoglobin concentration) and triggered an immune response by injecting lipopolysaccharides. Although we found that nestlings with lower body mass index had higher local survival rates, we found no support for the proposed hypothesis: neither baseline immune function nor the induced immune response of nestlings was associated with parental morph combination. Our results suggest that these immune parameters are unlikely to be involved in providing a selective advantage for the different colour morphs' offspring, and thus innate immunity does not appear to be traded off against a greater allocation of resources to somatic growth. Alternative hypotheses explaining the mechanism of a low nestling body mass index leading to subsequent higher local survival could be related to the post-fledgling dependency period or differences in dispersal patterns for the offspring from different morph combinations.

A tiny, long-legged raptor from the early Oligocene of Poland may be the earliest bird-eating diurnal bird of prey.

We report a small hawk-like diurnal bird from the early Oligocene (30-31 million years ago) of Poland. Aviraptor longicrus, n. gen. et sp. is of a size comparable with the smallest extant Accipitridae. The new species is characterized by very long legs, which, together with the small size, suggest an avivorous (bird-eating) feeding behavior. Overall, the new species resembles extant sparrowhawks (Accipiter spp.) in the length proportions of the major limb bones, even though some features indicate that it convergently acquired an Accipiter-like morphology. Most specialized avivores amongst extant accipitrids belong to the taxon Accipiter and predominantly predate small forest passerines; the smallest Accipiter species also hunts hummingbirds. Occurrence of a possibly avivorous raptor in the early Oligocene of Europe is particularly notable because A. longicrus coexisted with the earliest Northern Hemispheric passerines and modern-type hummingbirds. We therefore hypothesize that the diversification of these birds towards the early Oligocene may have triggered the evolution of small-sized avivorous raptors, and the new fossil may exemplify one of the earliest examples of avian predator/prey coevolution.

Care of the Geriatric Raptor.

Despite falconry having been practiced for centuries and with a wealth of published material on the husbandry of captive raptors over that period, there is a paucity of published material on the care of the geriatric raptor. Raptors are often a long-lived species and can suffer a range of age-related conditions that may impact on their welfare. This article seeks to cover some of these conditions and look at welfare considerations in the management of geriatric raptors, including quality-of-life assessments and euthanasia decision making.

Prey size as a critical factor for bird bone taphonomy in Eagle Owl (Bubo bubo) pellets.

Each predator hunts and consumes its prey in a particular way. Consequently, the traces left by predators on bones might vary according to the manner in which the prey are processed. For this reason, prey size has been proposed as a key issue that affects the damage inflicted on bones. The Eagle Owl (Bubo bubo) is one of the main potential predators of small prey found in archaeological sites. However, detailed taphonomic research describing bone accumulations produced by this nocturnal raptor is still scarce. The aim of the present work is to describe a modern accumulation of pellets originated by the Eagle Owl from this perspective, with a specific focus on birds. Particular attention is paid to prey size to evaluate the real significance of this variable when assessing bone damage. The results confirm that bone alterations reflect how prey was ingested, as the bones show greater damage with increasing prey size. This finding emphasises the complexity of characterising archaeological accumulations, as the alterations will vary according to prey size. In addition, bone architecture-or other aspects that cannot be controlled-may hinder accurate diagnosis and should be taken into account.

When and where mortality occurs throughout the annual cycle changes with age in a migratory bird: individual vs population implications.

The annual cycle of most animals is structured into discrete stages, such as breeding, migration and dispersal. While there is growing appreciation of the importance of different stages of an organism's annual cycle for its fitness and population dynamics, almost nothing is known about if and how such seasonal effects can change through a species lifespan. Here, we take advantage of the opportunity offered by a long-term satellite/GPS-tracking study and a reliable method of remote death-detection to show that certain stages of both the annual and life cycle of a migratory long-lived raptor, the Black kite Milvus migrans, may represent sensitive bottlenecks for survival. In particular, migratory journeys caused bursts of concentrated-mortality throughout life, but the relative importance of stage-specific survival changed with age. On the other hand, the balance between short-stages of high mortality and long-stages of low mortality made population-growth similarly dependent on all portions of the annual cycle. Our results illustrate how the population dynamics of migratory organisms can be inextricably linked to ecological pressures balanced over multiple stages of the annual cycle and thus multiple areas of the globe, suggesting the frequent need for challenging conservation strategies targeting all portions of a species year-round range.

Urban living predicts behavioural response in a neotropical raptor.

Behaviour is expected to be one of the most important factors driving urban living of bird species because it largely determines how animals interact with their environments. The contribution of different behavioural traits as facilitators of contemporary process of bird colonization of urban environments, however, is still unclear. Here we examined the differences in three behavioural traits: neophobia (avoidance of a new object) and solving success and solving latency of a problem solving test related to obtain food, in rural and urban living individuals of a common diurnal Neotropical raptor, the chimango caracara (Phalcoboenus chimango). Moreover, for solving success and solving latency behaviours, we tested the plasticity (i.e., habituation) in birds. Urban and rural chimangos showed similar neophobia of a new object. All chimangos showed an improvement in their output in problem-solving test as the five-day testing passed but urban chimangos showed higher solving capabilities than rural conspecifics as they were more successful in solving the problem test. More, urban birds shown lower solving latency than rural, as they were able to improve their test performance by opening doors in less time as the day passed; in rural birds this relation was not so abrupt. In addition, those individuals that opened more doors, opened these faster too. Lastly, both solving success and latency showed very low individual consistency (repeatability < 0.275). Our results provide evidence of plasticity in solving capabilities of chimango caracaras which reveal that a habituation process in these behavioural traits could be associated to establishment of birds in urban environments.

Comparing the toepads of Australian diurnal and nocturnal raptors with nonpredatory taxa: Insights into functional morphology.

The ventral structures of the avian digits are the critical interface between a bird and the item within its grasp (e.g., prey, landing substrate, or object), and as such are vital for ensuring the hunting success and survival of predatory birds. Here, we present the first descriptive analysis of the ventral structures of the toes, toepad morphology, and toepad surface area of several diurnal (Accipitriformes and Falconiformes) and nocturnal species (Strigiformes) of Australian raptors. We compare these with nonpredatory taxa (passeriform and psittaciform) to elucidate possible functional explanations for these differences. Although all groups shared the structural characters of joint, phalanx, ungual, and central (tarsal) pad features, the positioning of these structures in relation to the underlying skeletal framework and subsequent gross morphology differed markedly. Toepads overlying the phalangeal joints were much more developed in raptorial species with protrusional toepads only found on goshawks (Accipiter sp.), falcons, and owls. In contrast, the ventral surface of representative passeriform and parrot species showed overall uniformity in contact surface area, with much flatter toepads. There was only a very low phylogenetic signal in the data indicating that phylogenetic relationships did not have a significant effect on toepad surface area. Linear discriminant analysis indicated that functional prey sizes correlated positively with toepad surface areas. Generalized linear modelling showed that there was a positive, significant relationship between body mass and toepad surface area, and prey category significantly affected the toepad surface areas for Digit I and Digit IV. Overall, the ventral surface of the raptorial foot is subject to considerable variation, with active hunters showing the greatest differences in structures, specifically markedly developed toepads to protrusional toepads, potentially as a means to enable more efficient predatory behaviors and facilitate diet preferences for more difficult to catch prey items.

Measures of predator diet alone may underestimate the collective impact on prey: Common buzzard Buteo buteo consumption of economically important red grouse Lagopus lagopus scotica.

Human-wildlife conflicts often centre on economic loss caused by wildlife. Yet despite being a major issue for land-managers, estimating total prey losses to predation can be difficult. Estimating impacts of protected wildlife on economically important prey can also help management decisions to be evidence-led. The recovery in population and range of common buzzards Buteo buteo in Britain has brought them into conflict with some gamebird interests. However, the magnitude of any impact is poorly understood. We used bioenergetics models that combine measures of buzzard abundance from field surveys with diets assessed by using cameras at nests, prey remains and pellet analysis, to estimate their impact on red grouse Lagopus lagopus scotica on a large (115 km2) moor managed for red grouse shooting in Scotland. Whilst grouse consumption by individual buzzards was lower than previous estimates for other raptor species present on our study site, total consumption could be greater given an estimated 55-73 buzzards were present on the study site year-round. Averaging across diet assessment methods, consumption models estimated that during each of three breeding seasons (April-July 2011-2013), the buzzards foraging on our study site consumed 73-141 adult grouse and 77-185 chicks (depending on year). This represented 5-11% of adult grouse present in April (22-67% of estimated adult mortality) and 2-5% of chicks that hatched (3-9% of estimated chick mortality). During two non-breeding seasons (August-March), consumption models using pellet analysis estimated that buzzards ate a total of 242-400 grouse, equivalent to 7-11% of those present at the start of August and 14-33% of estimated grouse mortality during the non-breeding season. Buzzard consumption of grouse has the potential to lead to non-trivial economic loss to grouse managers, but only if buzzards predated the grouse they ate, and if grouse mortality is additive to other causes.

Insights into the development of a juvenile harpy eagle's hunting skills / Considerações sobre o desenvolvimento da habilidade de caça de um gavião-real juvenil

The post-fledging period is of paramount importance for raptors, since this is when a juvenile develops its hunting skills and gains the abilities required in adulthood and independence through dispersal. Little is known however, about this stage in the lives of raptors such as harpy eagles, Harpia harpyja. Between March 2016 and July 2017, we recorded three predation attempts on groups of primates by a wild juvenile harpy eagle in southwestern Brazilian Amazonia, including the first predation of an adult squirrel monkey, Saimiri ustus. These sequential records give insights into the gradual development of hunting skills during the post-fledging period, similar to what has been reported for other birds of prey. We hypothesize that a link between developing flight skills, decreasing parental food provisioning and increasingly successful captures triggers adulthood and independence in harpy eagles. (AU)

O período pós-emplumagem é de suma importância para os rapinantes, pois é quando um jovem desenvolve a habilidade de caça necessária na idade adulta e a independência por meio da dispersão. Entretanto, pouco se sabe sobre esse estágio na vida de rapinantes como o gavião-real, Harpia harpyja. Entre março 2016 e julho 2017, três tentativas de predação sobre grupos de primatas por um gavião-real juvenil foram registradas no sudoeste da Amazônia brasileira, incluindo a primeira predação de um macaco-de-cheiro adulto, Saimiri ustus. Estes registros sequenciais indicam um desenvolvimento gradual da habilidade de caça ao longo do período de pós-emplumagem, de forma similar ao relatado para outros rapinantes. Hipotetizamos que a associação entre o desenvolvimento da habilidade de voo, diminuição do provisionamento pelos pais e aumento da taxa de capturas bem-sucedidas promove a maturidade e independência no gavião-real.(AU)

Raptor talon shape and biomechanical performance are controlled by relative prey size but not by allometry.

Most birds of prey (raptors), rely heavily on their talons for capturing prey. However, the relationship between talon shape and the ability to take prey is poorly understood. In this study we investigate whether raptor talons have evolved primarily in response to adaptive pressures exerted by different dietary demands, or if talon morphology is largely constrained by allometric or phylogenetic factors. We focus on the hallux talon and include 21 species in total varying greatly in body mass and feeding ecology, ranging from active predation on relatively large prey to obligate scavenging. To quantify the variation in talon shape and biomechanical performance within a phylogenetic framework, we combined three dimensional (3D) geometric morphometrics, finite element modelling and phylogenetic comparative methods. Our results indicate that relative prey size plays a key role in shaping the raptorial talon. Species that hunt larger prey are characterised by both distinct talon shape and mechanical performance when compared to species that predate smaller prey, even when accounting for phylogeny. In contrast to previous results of skull-based analysis, allometry had no significant effect. In conclusion, we found that raptor talon evolution has been strongly influenced by relative prey size, but not allometry and, that talon shape and mechanical performance are good indicators of feeding ecology.

A mathematical model to describe the demographic dynamics of long-lived raptor species.

Population viability analysis of threatened large and long-lived raptor species has strong limitations due to the restricted demographic information available for these species. In this work, we mathematically model the demographic dynamics of these raptor species through time-indexed branching processes. By assuming the more general non-parametric statistical setting, we determine accurate estimates for the most relevant reproductive parameters involved in the model. To this end, we propose an algorithm based on approximate Bayesian computations methods. As illustration, by using real data of counts of the number of pairs in the population, we apply the proposed statistical and computational methods to describe the demographic dynamics of the Eurasian black vulture colony located at National Park of Monfragüe (Spain), which appears to be both the largest and densest breeding colony worldwide. In the scenario of these data-poor species, the class of time-indexed branching processes introduced appears to be appropriate and a more cost-effective method to evaluate dynamics and viability of the populations, applicable to the conservation of these taxa.

Lead in piscivorous raptors during breeding season in the Chesapeake Bay region of Maryland and Virginia, USA.

Sources of lead exposure of many bird species are poorly understood. We analyzed blood lead concentrations from osprey (n = 244; Pandion haliaetus) and bald eagles (n = 68; Haliaeetus leucocephalus) and documented potential sources of lead they may encounter. Adult bald eagles had higher blood lead concentrations than did adult osprey. However, blood lead concentrations of nestlings were similar for both species. Although 62% of osprey had detectable lead concentrations ( x¯ = 1.99 ± 4.02 µg/dL, mean ± standard deviation [SD]), there was no difference in the detection frequency or lead concentrations between osprey adults and nestlings. Likewise, we found no differences in the detection frequency or lead concentrations in osprey adults and nestlings from high- and low-salinity areas. Of the bald eagle samples tested, 55% had detectable lead levels ( x¯ = 6.23 ± 10.74 µg/dL). Adult bald eagles had more detectable and higher lead concentrations than did nestlings or pre-adults. Among environmental samples, paint had the highest lead concentrations, followed by sediment, blue catfish (Ictalurus furcatus), and gizzard shad (Dorosoma cepedianum). There was no correlation between blood lead concentrations of osprey adults and their offspring. Our results indicate that, in the Chesapeake Bay region of Maryland and Virginia (USA), there are multiple sources by which piscivorous raptors may be exposed to lead. Environ Toxicol Chem 2019;38:862-871. © Published 2019 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Luck in Food Finding Affects Individual Performance and Population Trajectories.

Energy harvesting by animals is important because it provides the power needed for all metabolic processes. Beyond this, efficient food finding enhances individual fitness [1] and population viability [2], although rates of energy accumulation are affected by the environment and food distribution. Typically, differences between individuals in the rate of food acquisition are attributed to varying competencies [3], even though food-encounter rates are known to be probabilistic [4]. We used animal-attached technology to quantify food intake in four disparate free-living vertebrates (condors, cheetahs, penguins, and sheep) and found that inter-individual variability depended critically on the probability of food encounter. We modeled this to reveal that animals taking rarer food, such as apex predators and scavengers, are particularly susceptible to breeding failure because this variability results in larger proportions of the population failing to accrue the necessary resources for their young before they starve and because even small changes in food abundance can affect this variability disproportionately. A test of our model on wild animals indicated why Magellanic penguins have a stable population while the congeneric African penguin population has declined for decades. We suggest that such models predicting probabilistic ruin can help predict the fortunes of species operating under globally changing conditions.