Necrosyrtes Research Articles

Perceptions on population decline and ethno-cultural knowledge of Hooded Vulture (Necrosyrtes monachus) in southwest States of Nigeria.

The global decline of many vulture populations due to anthropogenic activities is increasing and is largely connected to cases of poisoning. The objectives of this study were to access local perceptions and knowledge of vulture declines, and to determine the ethno-cultural uses of vulture body parts across southwest Nigeria. Semi-structured questionnaires were administered through interviews with randomly selected respondents (n = 144) between August 2018 and July 2019. Results showed that 82.5% (n = 119) of respondents confirmed the sharp decline in vulture populations. 79.8% (n = 115) of respondents considered poisoning to be the cause of vulture deaths in the study area and 79.8% (n = 117) confirmed the need to conserve the remaining vultures. 80.5% (n = 116) of respondents reported that vultures play a key role in Yoruba traditional settings. Vulture parts (organs) were reported as being important in ethno-cultural traditional benefits ranging from curing ailments, to making financial fortune to enhancing dreams, having visions about the future, healing and magic use. Conservation education and public awareness to shift the public mindset away from the use of vultures for rituals and healing purposes and the resultant negative effect of extirpation and extinction is the only way forward.

Homogeneity in cranial biometrics and bill morphology is verified by measurements from The Gambia, Botswana and Kenya in the case of the putative sub-species of the highly commensal Hooded Vulture Necrosyrtes monachus monachus and non-commensal Necrosyrte

We present biometrical data assembled from a combined total of 37 complete and partially cleaned skulls and feathered heads for the two putative subspecies of Hooded Vulture Necrosyrtes monachus monachus and N. m. pileatus (which Mundy et al. (1992) credibly argue should be N. m. carunculatus). We report on mostly insignificant variation in measurements taken from across three regions of the Hooded Vulture range. For N. m. pileatus (n = 22) the measurements are assembled from 13 live birds captured, tagged and released in Botswana between 2014-2017, seven museum specimens held in The National Museums of Kenya collected during 1913-1950, and two as described below. We compare with N. m. monachus (n = 14) where we measured eight specimens produced by road traffic accidents in The Gambia 2002-2019 of which seven are cleaned bare skulls and one a feathered study skin. We also measured six feathered heads and three skulls from several different countries in Africa, collected during 1832-1929 (n = 6 monachus, 2 pileatus, and 1 unknown) and held at the Natural History Museum, Tring, UK. Cranial materials for Hooded Vulture are scarce in world museums and the Gambian sample consisting of seven cleaned skulls represents the largest known number for a single country. Different populations across the regions vary considerably in both feeding habits and home ranges. We hypothesised that different foraging ecologies may have led to adaptation in bill morphology. Presented here for the first time are a series of skull morphometrics which test for variation in cranial biometrics and bill morphology from across the range of the Hooded Vulture. The Gambian bird has been DNA sequenced and a planned genetics study of other populations will resolve the long-standing taxonomic debate.

Vulture numbers and densities in a large protected savannah in West Africa

A number of vulture species were ubiquitous in undisturbed West African savannahs. However, in recent decades most species have declined rapidly and some are now at the brink of extinction. For some species, large protected areas are their last strongholds, but even there pronounced declines have become obvious in recent years. However, we lack even basic knowledge about current distribution, densities, movement patterns and threats. Comoé National Park (CNP) in northeast Côte d’Ivoire is one of the largest protected savannahs in West Africa and still hosts breeding populations of three critically endangered species (Hooded Vulture Necrosyrtes monachus, White-backed Vulture Gyps africanus, White-headed Vulture Trigonoceps occipitalis). In total, 590 km of searches for vultures and their nests were conducted on foot in southwest CNP in the dry seasons of 2018 and 2019. Thirty-seven active vulture nests (Hooded Vulture – 2, White-backed Vulture – 32, White-headed Vulture – 3) were discovered. CNP may be one of the last refuges for these species in Côte d’Ivoire and important for their conservation in West Africa. There are, however, hints that vultures have declined in CNP since the 1990s and are now rarer especially at the Park's fringe. Together with observations of increasing poaching activities, this underlines that large reserves with strict law-enforcement are needed to save West Africa's vultures from extinction.

Predicting residents' intention to conserve the hooded vulture (Necrosyrtes monachus) in the Birem North District, Ghana

The vulture as an important and specialized scavenger in human societies, helps clean the environment and prevents diseases. However, plummeting populations across the globe in the last three decades has led to the classification of some species as endangered and critically endangered. This study predicts the intention of residents to support conservation of the hooded vulture in communities near a mine site in the Eastern region of Ghana. Novelty of the current study lies in the use of a social psychology theory to prognosticate human attitude towards a potential vulture population increase. The Theory of Planned Behavior was used as the study framework while data was collected through household survey. The questionnaire assessed attitudes of residents towards the vulture based on a wide range of issues, using a five-point Likert scale. The results indicate that respondents have strong attitudinal disposition towards non-persecution of vultures – a salient determinant of intention to support vulture conservation (r = 0.66, N = 281, p < 0.01). Variables reflecting attitudes and subjective norm were significant predictors of intention to support vulture conservation but perceived behavioral control was not significant. Interventions aimed at conserving vultures in the study area may succeed if strategies highlight the importance of avian scavengers in human societies and target change in personal attitudes that favor nature conservation in general.

Variation in monthly sizes of home‐ranges of Hooded Vultures Necrosyrtes monachus in western, eastern and southern Africa

Tracking studies are often used to inform conservation plans and actions. However, species have frequently only been tracked in one or a few localities, whereas space use can be remarkably flexible, especially in long‐lived species with advanced learning abilities. We assessed variability in space use in the Critically Endangered Hooded Vulture Necrosyrtes monachus by pooling movement data from three populations across the species’ sub‐Saharan range (in South Africa, Botswana, Ethiopia, Kenya, The Gambia and Mozambique). We estimated minimum convex polygons and kernel density estimators (KDEs) and compared monthly home‐range sizes between breeding and non‐breeding seasons, age‐classes and subspecies, accounting for uneven sampling within groups. Mean (± sd) monthly home‐range sizes (95% KDEs) for adult Hooded Vultures from southern (12 453 ± 21 188 km2, n = 82) and eastern Africa (3735 ± 3652 km2, n = 24) were 103 and 31 times larger than those of conspecifics from western Africa (121 ± 98 km2, n = 48). This may relate partly to subspecific differences, and individuals with small home‐ranges in western Africa and Ethiopia were trapped in urban environments. Regional variation in space use by Hooded Vultures may be linked to flexibility in feeding behaviour (degree of commensalism) which may arise in response to resource availability and persecution in different areas. Age‐class also affected monthly home‐range sizes, with immature birds generally having larger monthly home‐range size estimates than adults. Our results highlight the flexibility of Hooded Vultures in terms of their home‐range sizes and suggest that home‐range sizes differ between populations and individuals, depending on the extent of human commensalism. Our results also reaffirm the importance of international co‐operation in conservation efforts aimed at protecting this wide‐ranging, non‐migratory species.

Captive large predators killing vultures: exposing captive facilities as an additional source of mortality to highly threatened birds

Background and objective: African vultures are under pressure from various, well-known anthropogenic threats. Here we describe and aim to highlight a littleknown source of mortality to two Critically Endangered vulture species (Gyps africanusand Necrosyrtes monachus), as well as the Endangered Cape Vulture (Gyps copropheres) in southern Africa – that of captive big cats killing vultures that land in their enclosures to feed on food scraps or faeces or to bathe in drinking water.Methods: Personal observations, reports from public, interviews with current and former staff from predator parks and lion hunting ranches.Discussion: While the spatial and numerical extent of this mortality has not yet been quantified, if it is found to be widespread then failure to address it may present a risk to the regions’ vulture populations.Conclusion: We encourage captive breeding facilities and regulatory authorities to take appropriate action to prevent free-roaming vultures from coming into contact with captive big cats, and we highlight the need for further research todetermine the spatial extent and magnitude of this threat to African vultures.

Gulper, ripper and scrapper: anatomy of the neck in three species of vultures.

The head-neck system of birds is a highly complex structure that performs a variety of demanding and competing tasks. Morphofunctional adaptations to feeding specializations have previously been identified in the head and neck, but performance is also influenced by other factors such as its phylogenetic history. In order to minimize the effects of this factor, we here analyzed the anatomy of three closely related vultures that distinctly differ in feeding strategy. Vultures, as obligate scavengers, have occupied a special ecological niche by exclusively feeding on carrion. However, competition among sympatric vultures led to ecological differences such as preference of certain types of food from a carcass. Via comparative dissections we systematically described the craniocervical anatomy in the Griffon vulture (Gyps fulvus), the Cinereous vulture (Aegypius monachus) and the Hooded vulture (Necrosyrtes monachus) that exploit the same food resources in different ways. Our results revealed differences in the number of cervical vertebrae, in the morphology of the atlas-axis complex as well as in the neck musculature despite overall similarities in the musculoskeletal system. Gulpers, rippers and scrappers adopt specific postures while feeding from a carcass, but the cervical vertebral column is indispensable to position the head during all kinds of behavior. The great range of demands may explain the conservation of the overall muscle topography of the neck across the studied taxa.

A review of the use of birds’ nests by Egyptian geese, including a breeding attempt in a hooded vulture nest

Egyptian geese Alopochen aegyptiaca are widely reported to be territorial and aggressive. They are known to attack and sometimes kill other birds and they may attempt to usurp their nests. Here information is collated on the bird species whose nests have been used or usurped by Egyptian geese. Also presented are observations from a series of camera trap images of an Egyptian goose laying eggs and incubating in a hooded vulture Necrosyrtes monachus nest to which a juvenile hooded vulture returned repeatedly for food. Ten aggressive encounters were recorded between the Egyptian goose and the hooded vultures; the goose prevailed in five of these encounters, the vultures in four and on one occasion both vultures and goose fled the nest. This is the first time that an Egyptian goose has been recorded breeding in a hooded vulture nest. The hooded vulture chick successfully fledged and although the goose incubated for at least 20 days, for reasons unknown, its breeding attempt ultimately failed.

Vulture declines, threats and conservation: the attitude of the indigenous Ghanaian

SummaryUnderstanding the attitude of people towards vultures, especially factors that influence behaviours that support their conservation, is crucial if the decline in vultures is to be slowed and reversed. Their vital ecosystem function in keeping the environment free of carcasses and reducing the spread of disease is not yet appreciated in Ghana. Little is known about the attitude of Ghanaians’ about vultures. Structured questionnaires and key informant surveys were employed with a sample size of 460 respondents randomly selected across Ghana. Over 85% of respondents were familiar with the Hooded Vulture Necrosyrtes monachus and vultures were culturally important to 56% of respondents. Diseases that affect livestock are claimed to be treated with chemicals such as diclofenac sodium to which vultures are highly susceptible globally and livestock carcasses were not available to vultures as 53% of respondents bury carcasses. A new poisoning pathway has emerged in which furadan is used to poison wildlife for bushmeat and the offal removed which is then consumed by vultures, as indicated by 78% of respondents. The majority of respondents positively thought vultures were important and must be protected. Poisoning, habitat loss particularly the loss of silk cotton tree Ceiba pentandra and trade in vulture parts for traditional medicine are major threats to vultures in Ghana. Continuous awareness creation, positive attitude towards the environment, vulture conservation programmes and protection of breeding sites were some urgent conservation actions recommended to ensure the survival of vultures.

Low genetic diversity and shallow population structure in the endangered vulture, Gyps coprotheres

Globally, vulture species are experiencing major population declines. The southern African Cape vulture (Gyps coprotheres) has undergone severe population collapse which has led to a listing of Endangered by the IUCN. Here, a comprehensive genetic survey of G. coprotheres is conducted using microsatellite markers. Analyses revealed an overall reduction in heterozygosity compared to other vulture species that occur in South Africa (Gypaetus barbatus, Necrosyrtes monachus, and Gyps africanus). Bayesian clustering analysis and principal coordinate analysis identified shallow, subtle population structuring across South Africa. This provides some support for regional natal philopatry in this species. Despite recent reductions in population size, a genetic bottleneck was not detected by the genetic data. The G. coprotheres, however, did show a significant deficiency of overall heterozygosity. This, coupled with the elevated levels of inbreeding and reduced effective population size, suggests that G. coprotheres is genetically depauperate. Given that genetic variation is considered a prerequisite for adaptation and population health, the low genetic diversity within G. coprotheres populations is of concern and has implications for the future management and conservation of this species.

Impact of human activities on the reproduction of Hooded Vultures Necrosyrtes monachus in Burkina Faso

During the last decades, the critically endangered Hooded Vulture Necrosyrtes monachus has strongly declined across its African range. Although direct persecution has been suggested as a major cause of this decline, little is known about the impact of humans on reproductive output in West Africa. We studied the impact of human activities on the reproductive output of Hooded Vultures in the Garango area of Burkina Faso. Twenty and 56 nesting attempts were monitored, respectively, during the breeding season in 2013/14 and 2014/15, to determine reproductive success and identify causes of nest failure. Annual breeding success varied between 0.68 and 0.71 chicks fledged per breeding pair per year and productivity was assessed at 0.57 chicks fledged per territorial pair in 2014/15. The main threats imposed by humans were poaching of eggs, chicks and collection of nest materials, leading to 20% (13 out of 64 breeding attempts) of nest failures over the two years. An additional important reason for nest failure was the pruning and (partial) cutting of nest trees. Despite this high level of human interference, we found that Hooded Vulture nest success increased with proximity to human settlements, probably because breeding vultures benefit from protection by people against persecution and disturbance.

Home-range size and movement patterns of Hooded Vultures Necrosyrtes monachus in southern Africa

Hooded Vulture Necrosyrtes monachus populations have declined dramatically in recent years, but we know little about their ecology. We radio-tagged four vultures in northern Botswana to gather data on animal movement and home-range patterns. Hooded Vultures were primarily sedentary at night. Hooded Vultures moved similar distances and speeds during the wet and dry season, and travelled over similar home ranges as measured using minimum convex polygons (MCP), but used much smaller core areas during the dry (breeding) season. We found significant differences in mean distances and speeds moved among different birds, and when comparing day to night, but not between the wet (non-breeding) and dry (breeding) season or by year. All of the variables we tested, including individual vulture differences, season, year and number of fixes, significantly influenced 95% MCP and kernel density estimate (KDE) home-range sizes. Hooded Vultures used significantly smaller KDE home-range sizes during the dry (breeding season) than in the wet (non-breeding) season. Hooded Vultures travelled smaller daily distances over smaller home ranges than most other vulture species for which data exist.

Traditional medicine trade in vulture parts in northern Nigeria

We report findings on the vulture trade in northern Nigeria, where it is commonly practised especially to supply the traditional medicine industry. We administered an open-ended questionnaire to 113 traditional, predominantly Hausa medicinal traders in 39 markets within eight states in northern Nigeria. Of the interviewed traders, 78% only had feathers of vultures on display in their stalls, 11% also offered vulture heads and 4.4% offered entire vultures; 40% of traders sold vultures for spiritual healing and 25% sold vultures for consumption. Forty-three percent of traders were supplied most often from vulture populations inside Nigeria and 48% were principally supplied from other countries in the region, as far west as Benin and east to Sudan. Increased prices for parts during the past 10 years reflected similar, or perhaps increasing, demand but lower availability of vultures. Hooded Vulture (Necrosyrtes monachus) was the commonest species traded with 90% of parts belonging to this species. Vultures sold in stalls had been killed using agricultural chemicals, shotguns, traps, and ground tobacco powder. Urgent and drastic conservation measures are needed to prevent further exploitation of critically endangered vultures in Nigeria and surrounding countries.Keywords: traditional medicine, vulture trade, northern Nigeria, conservation

Not in wilderness: African vulture strongholds remain in areas with high human density.

Vultures constitute an important functional group in many ecosystems, providing crucial ecosystem services both in natural and humanized environments. These scavengers are facing massive declines worldwide, but in several African countries virtually nothing is known on populations’ status and threats, hampering the development of adequate conservation strategies. In Guinea-Bissau, globally important populations of Hooded Necrosyrtes monachus and African white-backed vultures Gyps africanus were recently reported. Using the country as a study area, we aim to characterize human-vulture interactions in West Africa applying a multidisciplinary approach. We assessed the status and distribution of vulture populations using data from 1711 km of roadside transects, examined predictors of their distribution, and produced a nationwide population estimate for the Hooded Vulture, using an innovative method based on the relationship between the size of human population in settlements and vulture numbers. We conducted 47 stakeholder interviews to assess perceived roles played by vultures, and to investigate potential anthropogenic threats. Hooded vultures were strongly associated with high human population densities, whereas no relation was found between African white-backed and Rüppell’s vultures and any of the tested predictors, which included cattle density, precipitation and Normalized Difference Vegetation Index, among others. We estimate a national population of 43347 Hooded vultures, the largest population reported in the species range. Respondents were generally aware of the services provided by vultures, especially waste and carcass removal, including in urban areas. Hunting for witchcraft and traditional medicine was the most frequently recognised threat, while poisoning was ranked as having the highest impact. We hypothesise that poisoning-related mortality may be affecting African white-backed and Rüppell’s vultures’ distribution and explain their scarcity in apparently highly suitable habitats. Our results suggest a mutualistic rather than a commensalistic relationship between vultures and humans, with important implications for designing and implementing conservation strategies.

Visitors to nests of Hooded Vultures Necrosyrtes monachus in northeastern South Africa

Hooded Vultures Necrosyrtes monachus are critically endangered but little is known of their year-round use of nests or whether other species usurp Hooded Vulture nest sites. We investigated visitation rates by Hooded Vultures and other species (including potential nest predators and usurpers) to examine their effect on Hooded Vulture breeding success. We present observations of 33 species recorded by camera traps at 12 Hooded Vulture nests over a total of 93 nest-months (2 095 nest-days). Several pairs of Hooded Vultures visited their nests regularly during the non-breeding season, some adding nesting material, highlighting that pairs visited their nest(s) year round. Egyptian Geese Alopochen aegyptiaca, potential usurpers of raptor nests, were present at occupied and unoccupied Hooded Vulture nests, but we recorded no usurpation of nests by Egyptian Geese and they had no impact on vulture breeding success. Hooded Vulture breeding failure was linked to two species only: camera-trap imagery recorded one case of predation of a vulture egg by a Chacma Baboon Papio ursinus, and one case of a Martial Eagle Polemaetus bellicosus predating a vulture nestling. We recommend expanding the Hooded Vulture nest monitoring programme to include more pairs.

The decline of an urban Hooded Vulture Necrosyrtes monachus population in Dakar, Senegal, over 50 years

As in many West African cities, in Dakar Hooded Vultures Necrosyrtes monachus have always been characteristic urban scavengers. The recent decline of Hooded Vultures in other parts of Africa, mainly eastern Africa, has been the reason in 2015 for up-listing of its status by the IUCN in the Red List of Threatened Species to Critically Endangered. As the Hooded Vulture is still common in the Lower Casamance, Senegal, in the Western Region of The Gambia and in Guinea-Bissau, without clear signs of a recent decrease, a survey of its current status in Dakar was undertaken and compared with historical data over the past 50 years. A strong decrease of >85% was noted from 3 000 individuals in 1969 to 400 in 2016. This decline is on the high end of the decline noticed over much of its range but in striking contrast with the apparently stable populations along the West African coast more to the south (The Gambia to Guinea). Likely causes are (1) exponential urbanisation resulting in loss of feeding sites and reduced food availability, (2) increased poisoning of feral dogs with strychnine sulphate due to an upsurge of rabies and (3) increased disappearance of suitable trees for nesting and roosting.

Status of birds of prey in Guinea-Bissau: first assessment based on road surveys

Several studies have reported marked declines in populations of birds of prey across the African continent, including West Africa. However, there are still regions of which virtually nothing is known, as is the case for Guinea-Bissau. Because birds of prey play important roles in ecosystems and several species are threatened, it is important to establish baseline knowledge on their status. This is the first study in the country focusing exclusively on birds of prey. We conducted 1 711 km of roadside transects from mid-February to the end of May 2016, covering most of Guinea-Bissau. In total 4 989 birds of 33 species were counted, of which Hooded Vultures Necrosyrtes monachus were the most common (252 birds per 100 km, the second highest abundance in all the species’ range). Observations outside transects, including during regular field trips throughout the country, particularly between 2012 and 2016, were used as complementary information adding 13 species to the list, and contributing three new species for Guinea-Bissau: Ayres’s Hawk-eagle Hieraaetus ayresii, Booted Eagle Hieraaetus pennatus and Lesser Kestrel Falco naumanni. Most species showed differences in abundance in relation to vegetation cover (based on the normalised difference vegetation index). Apart from Hooded Vultures and White-backed Vultures Gyps africanus, all other raptors in the IUCN Red List were found to be scarce, including other vultures and several medium-to-large eagles.

Removal (and attempted removal) of material from a Hooded Vulture Necrosyrtes monachus nest by a starling and a Hooded Vulture

Relatively little is documented about nest material theft in vultures. We used camera traps to monitor Hooded Vulture Necrosyrtes monachus nests for a year. We report camera trap photographs of a starling Lamprotornis sp. removing what appeared to be dung from an inactive Hooded Vulture nest on Cleveland Game Reserve, north-eastern South Africa, in October 2016. We also had evidence of a Hooded Vulture attempting to remove twigs from the same nest in August 2016. This behaviour is previously unrecorded in Hooded Vultures and, although seemingly rare, it represents an attempt to reduce the energetic costs of nest building in this species.

Hooded Vulture Necrosyrtes monachus and African White-backed Vulture Gyps africanus nesting at the Olifants River Private Nature Reserve, Limpopo province, South Africa

Basic ecological information is still lacking for many species of African vultures. The Hooded Vulture Necrosyrtes monachus is known as a rare breeding resident in north-eastern South Africa. This study set out to monitor the nests of Hooded Vultures and, secondarily, White-backed Vultures Gyps africanus in the Olifants River Private Nature Reserve over two breeding seasons in 2013 and 2014. A total of 12 Hooded Vulture nests, placed mostly in the tree Diospyros mespiliformis, were found along the Olifants River, with an average inter- nest distance of 0.76 km. Nest success was estimated to be between 0.44–0.89 offspring pair−1 y−1 in 2013 and 0.50–0.67 offspring pair−1 y−1 in 2014, which are the first estimates for Hooded Vultures in South Africa. It is thought that nests of this species have been under-reported due to the fact that they are placed within or below the canopy of densely leafed trees and hence difficult to view from aerial surveys. African White-backed Vultures also bred along the Olifants River, with nests placed in clusters of up to six. Nesting density of this species ranged from about 1.0 to 1.2 nests km−1 and nests were predominantly placed in Ficus sycomorus trees.

Assessment of the occurrence and threats to Hooded Vultures &lt;i&gt;Necrosyrtes monachus&lt;/i&gt; in western Kenyan towns

The Hooded Vulture Necrosyrtes monachus is endemic to Africa and has recently been uplisted to Endangered on the IUCN Red List. Populations of Hooded Vulture in Kenya have declined significantly in recent decades and urban populations exist primarily in western Kenya towns where they typically forage at slaughterhouses and dumpsites. We surveyed seven western Kenyan towns and one neighbouring Ugandan market centre to assess the occurrence and threats to this species using opportunistic observations and interviews with employees at slaughterhouses and dumpsite facilities. We observed 23 Hooded Vultures, 20 in Bungoma Town and 3 in Busia-Uganda. Scavenging vultures were only observed at open-air slaughterhouses or dumpsites. We conducted 34 interviews at 14 facilities of which 23 interviews from six facilities were determined to be of good quality and used for subsequent analyses. At four of the facilities employees confirmed that Hooded Vulture numbers had declined and two respondents indicated declines had occurred from the year 2000 onwards. Possible reasons for declines mentioned by respondents were the introduction of closed-system of slaughterhouses, poisoning of stray dogs, cutting of roost trees, and increased competition for food. There was little evidence of exploitation of the birds for witchcraft or for food.