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In 2013, we satellite-tracked four juvenile Levant Sparrowhawks Accipiter brevipes from their nests in southern Armenia. Mean departure date from summering areas was 30 August. During autumn, birds...

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Admission records of rescued birds are an important source of information for tracking the prevalence of human‐related threats to wildlife. In this study, we used admission records from January 2015 to December 2016 to review the causes for raptor admissions to a raptor rehabilitation centre in Pietermaritzburg, South Africa, and to determine factors that can be used to predict the outcome of rehabilitation. During the study period, 242 raptors were admitted to the centre, representing 33 species. The major causes of admission were collision‐related injuries (52%), grounded birds (12%) and orphaned chicks (10%). The most common casualties were spotted eagle‐owl Bubo africanus (23%), yellow‐billed kite Milvus migrans aegyptius/parasitus (12%), jackal buzzard Buteo rufofuscus (10%) and western barn owl Tyto alba (10%). The rehabilitation centre had a release rate of 48%. Reason for admission was a significant predictor of the outcome of rehabilitation while other variables were not. Raptors with no severe injuries such as orphaned chicks and grounded birds were more likely to have successful rehabilitation treatment than raptors suffering from collision injuries. Wildlife rehabilitators can use the results of the present study to develop triage guidelines for raptors admitted to rehabilitation centres.

Migration can be costly with consequences that can influence population trajectories. These costs and consequences are especially heightened during over-water travels, which can be high-risk events for birds. We created spatial models to evaluate potential migratory responses of “oceanic”, island-hopping grey-faced buzzards that encounter variation in landscape parameters and weather as they move through and out of the Philippine archipelago. We constrained the modeled routes to enter the island chain at Basco and to use one of four potential exit points in the south of the country, either Balabac, Bongao, Balut Island, or Cape San Agustin. We used all possible combinations of our three external parameters (stopover sites, water crossings and wind direction) to model alternative migratory routes for each of the four exit points (n = 20 migratory routes). Modeled grey-faced buzzard routes were between 1,582 and 2,970 km. Routes overlapped over eastern and central Luzon, along a leading line created by the Sierra Madre Mountains. Routes also overlapped and suggested unavoidable over-water crossings between Mindoro and Palawan, Negros and Zamboanga del Norte, and Leyte and Surigao. Our models suggest that the optimal migratory strategy for these birds is to find the shortest route to an exit point with the greatest possible access to stopover habitats and fewest open-water crossings under wind resistance. Understanding how each of these external factors affected the geography and characteristics of the migratory routes helps us to understand the context for different migratory strategies of birds that face dangerous open-water crossings on migration.

The ranging behaviour of raptors in human-altered environments, such as agricultural and suburban landscapes, is becoming increasingly important for conservationists in the context of unprecedented high rates of anthropogenic land use change. We studied the movement ecology of adult Long-crested Eagles Lophaetus occipitalis fitted with geographic positioning system transmitters in an agricultural landscape in KwaZulu-Natal Province, South Africa. Mean home ranges (± SD) of males and females estimated using the autocorrelated kernel density estimator (AKDE) method were 608 ± 552 ha (n = 5) and 664 ± 844 ha (n = 4), respectively. Core areas (KDEhref 50%) were estimated as 80 ± 38 ha and 39 ± 20 ha for males and females, respectively. We also recorded exploratory behaviour (in the form of long excursions) in two of the birds, of up to 49 km from the centre of their home range. The relatively small home ranges reported in this study are suggestive of productive foraging habitats whereby Long-crested Eagles can meet their energy requirements without having to travel long distances to obtain resources. Consistent with predictions, non-breeding male and female Long-crested Eagles showed similar ranging behaviour, which includes occasional exploratory behaviour.

This chapter explores the symbiotic relationship between humans and vultures, which date to when prehistoric hominins followed flights of vultures to large-mammal carcasses in East Africa. Several biological adaptations of vultures render them particularly vulnerable to human threats. These include feeding on dead animals that have been poisoned, eating large amounts of food at a single meal, and feeding together at “common tables,” all of which expose large numbers of vultures to contaminants simultaneously. Today, principal human threats to vultures and condors are land-use change; environmental contaminants, including veterinary drugs, the heavy metal lead, and pesticides; poisoning; and persecution, with the latter including catching and killing vultures as pests, for bushmeat and witchcraft, including as clairvoyants, and as sentinels of illegal poaching. Global climate change can also affect the distributions and abundances of avian scavengers in many ways. Creating a better understanding of the ecological functions and needs of vultures, along with monitoring their populations, are essential features of effective vulture conservation.

This chapter describes the various species of obligate scavenging birds of prey and their life histories. Vultures are widespread geographically; their populations are most numerous and their diversity highest in tropical and subtropical regions. Substantial differences in both the distributions and the abundances of individual species occur, and together with their different phylogenies and their anatomical and behavioral characteristics, all species distinguish themselves as unique biological entities. New World vultures include the Black Vulture, Turkey Vulture, Lesser Yellow-headed Vulture, Greater Yellow-headed Vulture, King Vulture, California Condor, and Andean Condor. Old World vultures include the Palm-nut Vulture, Bearded Vulture, Egyptian Vulture, Hooded Vulture, Indian Vulture, Slender-billed Vulture, White-rumped Vulture, Griffon Vulture, Rüppell's Vulture, Himalayan Vulture, White-backed Vulture, Cape Vulture, Red-headed Vulture, White-headed Vulture, Cinereous Vulture, and Lappet-faced Vulture.

This chapter examines pair formation and reproduction, which is an essential aspect of the biology of scavenging birds of prey. Vultures breed seasonally, especially in response to carcass and updraft availability. Excepting several larger and often more predatory species in which females are notably more massive than their male counterparts, males and females differ little in body mass, except for Andean Condors, in which males are larger than females. The Bearded Vulture, a species in which siblicide occurs, also exhibits reversed sexual size dimorphism—that is, the females are larger. Almost all vultures and condors delay maturity, most likely because it takes multiple years to develop carcass-searching and territorial skills necessary for successful breeding. Multi-year pair fidelity is typical in scavenging raptors, but extra-pair copulations do occur, as does within-year mate switching. Territoriality occurs in some, but not all, vultures. Breeding success, which varies with food availability, weather, and predation, appears to be high in many species, although this may be so because it has been studied in areas with relatively dense and, presumably highly successful, populations.

This chapter discusses the essential ecosystem function of microbial decomposition and carrion consumption by scavengers. Decomposers are single-celled, saprophytic or saprozoic organisms, including bacteria, which feed extracellularly on dead material on-site. Scavengers are multicellular organisms, including both invertebrates and vertebrates, which feed on the fragments of carcasses, either on-site or elsewhere. The ecological actions of decomposers and scavengers as elemental recyclers serve to recapture and supply the raw materials that other ecological entities, including plants and consumers, need to maintain the energetic processes of primary and secondary productivity necessary to sustain the long-term continuity of ecological systems. Although many carnivorous vertebrates are facultative scavengers that sometimes feed on carrion, the world's vultures are the only truly obligate vertebrate scavengers, species that feed almost entirely on carrion and that require carrion for their livelihoods.

This chapter focuses on food finding and feeding behavior of vultures. Carrion is neither as scarce nor as unpredictable as many scientists suggest, and vultures are well adapted to secure it. Vultures require and use low-cost, non-flapping, soaring flight to fly long distances when engaged in low-cost searching flight. Moreover, they use sight while searching for carrion. A few species also use smell and possibly sound to locate carrion and other nutritional resources. The chapter then explains how social facilitation resulting from both single and multi-species aerial information networks makes it possible for vultures to follow one another to carrion, which is an essential component of effective food finding in vultures. Behavioral competition among vultures at feeding sites is both kinetic and complex, and aggressive interactions can be intense. Vultures are sometimes, but not typically, cannibalistic. They also sometimes approach and hasten the demise of a dying animal, which they then feed upon even while it is still alive.