Foraging Ranges of Immature African White-Backed Vultures (Gyps africanus) and Their Use of Protected Areas in Southern Africa

Vultures in the Gyps genus are declining globally. Multiple threats related to human activity have caused widespread declines of vulture populations in Africa, especially outside protected areas. Addressing such threats requires the estimation of foraging ranges yet such estimates are lacking, even for widespread (but declining) species such as the African white-backed vulture (Gyps africanus). We tracked six immature African white-backed vultures in South Africa using GPS-GSM units to study their movement patterns, their use of protected areas and the time they spent in the vicinity of supplementary feeding sites. All individuals foraged widely; their combined foraging ranges extended into six countries in southern Africa (mean (± SE) minimum convex polygon area  = 269,103±197,187 km²) and three of the vultures travelled more than 900 km from the capture site. All six vultures spent the majority of their tracking periods outside protected areas. South African protected areas were very rarely visited whereas protected areas in northern Botswana and Zimbabwe were used more frequently. Two of the vultures visited supplementary feeding sites regularly, with consequent reduced ranging behaviour, suggesting that individuals could alter their foraging behaviour in response to such sites. We show that immature African white-backed vultures are capable of travelling throughout southern Africa, yet use protected areas to only a limited extent, making them susceptible to the full range of threats in the region. The standard approach of designating protected areas to conserve species is unlikely to ensure the protection of such wide-ranging species against threats in the wider landscape.     

Implications of bacterial,viral and mycotic microorganisms in vultures for wildlife conservation,ecosystem services and public health

The effects that microorganisms (bacteria, viruses and fungi) have on their hosts remain unexplored for most vulture species. This is especially relevant for vultures, as their diet consists of carcasses in various stages of decomposition, which are breeding grounds for potentially pathogenic microorganisms. Here we review current knowledge of bacterial, viral and mycotic microorganisms present in wild vultures. We consider their potential to cause disease in vultures and whether this poses any population-level threats. Furthermore, we address the question of whether vultures may act as disease spreaders or mitigators. We found 76 articles concerning bacterial, viral and mycotic microorganisms present in 13 vulture species, 57 evaluating bacteria, 13 evaluating viruses and six evaluating mycotic microorganisms. These studies come from all continents where vultures are present, but mainly from Europe and North America, and the most studied species was the Griffon Vulture Gyps fulvus. We found that vultures are colonized by zoonotic pathogens, and even host-specific human pathogens. Some recorded bacteria showed multi-antibiotic resistance, especially those that can be associated with anthropogenic food subsides such as supplementary feeding stations. We found evidence that vulture health can be affected by some microorganisms, producing a wide array of clinical alterations that have the potential to influence mortality risk and fitness. We did not find clear scientific evidence that vultures play an epidemiological role spreading microorganisms to humans and other species. However, there is evidence that vultures could prevent the spread of infectious diseases through their removal of decomposing organic material. The evaluation of vulture exposure to microorganisms is of fundamental importance to design better conservation policies for this threatened group, which may serve a key role as ecosystem cleaners.     

Bone crushing carnivores and their significance to osteodystrophy in griffon vulture chicks

The natural removal of 89 ungulate carcasses by predators and scavengers was monitored in various wildlife reserves and ranching areas of South Africa. Carnivores responsible for the bone remains were determined. Spotted hyaenas and, to a lesser extent, Brown hyaenas, were the only carnivores that regularly chewed bones. When hyaenas were absent, months of weathering were required before the smaller bones became disarticulated and able to be removed by vultures. The bone-collecting behaviour and related aspects of breeding of two species of griffon vulture were studied at five different nesting colonies in southern Africa—one Cape vulture colony and one White-backed vulture colony in or near wildlife reserves, as well as two Cape vulture colonies and one White-backed vulture colony in ranching land. A total of 2825 bones was found in or below the vulture nests. These bones were categorized and measured. Hyaena-produced bone fragments were found only in the colonies in the wild areas—none of the 387 chicks examined here had osteodystrophy (metabolic bone disease). By contrast, in the ranching areas, vultures collected larger and less fragmented bones. Many Cape vulture chicks had osteodystrophy (130 of 1917 examined), as did two White-backed vulture chicks (of 196 examined). In 1977, artificial feeding stations, 'restaurants' where carcass skeletons were crushed, were established for Cape vultures. Since then, the incidence of osteodystrophy has declined from 17% to 2–5% in 1983. It is clear that bone fragments are an essential dietary requirement, providing calcium for correct skeletal growth of griffon vulture chicks.     

Vulture flight behavior and implications for aircraft safety

Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solar-powered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006–30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than did turkey vultures in all seasons except summer when altitudinal distributions (above ground level) did not differ. Although we recorded maximum altitudes of 1,578 m for black vultures and 1,378 for turkey vultures, most flights were low altitude. A matrix of vulture flight altitude versus time of day revealed that >60% of vulture flight activity occurred from 4 hr to 9 hr after sunrise at altitudes below 200 m. Continuation of aggressive harassment coupled with flexible training schedules to avoid times and altitudes of high vulture activity will decrease hazards to aircraft posed by these birds. © 2011 The Wildlife Society.     

African Vultures Don’t Follow Migratory Herds: Scavenger Habitat Use Is Not Mediated by Prey Abundance

The ongoing global decline in vulture populations raises major conservation concerns, but little is known about the factors that mediate scavenger habitat use, in particular the importance of abundance of live prey versus prey mortality. We test this using data from the Serengeti-Mara ecosystem in East Africa. The two hypotheses that prey abundance or prey mortality are the main drivers of vulture habitat use provide alternative predictions. If vultures select areas based only on prey abundance, we expect tracked vultures to remain close to herds of migratory wildebeest regardless of season. However, if vultures select areas where mortality rates are greatest then we expect vultures to select the driest regions, where animals are more likely to die of starvation, and to be attracted to migratory wildebeest only during the dry season when wildebeest mortality is greatest. We used data from GSM-GPS transmitters to assess the relationship between three vulture species and migratory wildebeest in the Mara-Serengeti ecosystem. Results indicate that vultures preferentially cluster around migratory herds only during the dry season, when herds experience their highest mortality. Additionally during the wet season, Ruppell’s and Lappet-faced vultures select relatively dry areas, based on Normalized Difference Vegetation Index, whereas White-backed vultures preferred wetter areas during the wet season. Differences in habitat use among species may mediate coexistence in this scavenger guild. In general, our results suggest that prey abundance is not the primary driver of avian scavenger habitat use. The apparent reliance of vultures on non-migratory ungulates during the wet season has important conservation implications for vultures in light of on-going declines in non-migratory ungulate species and use of poisons in unprotected areas.     

Significant population of Egyptian Vulture Neophron percnopterus found in Morocco

The Egyptian Vulture Neophron percnopterus population in Morocco has undergone a marked decline since the 1980s to the point of nearing local extinction in the twenty-first century. A field study of some possible sites for Egyptian Vultures was carried out over six days during June 2014 in the Middle Atlas Mountains, Morocco. We counted a total of 48 Egyptian Vultures at three different localities: two occupied breeding sites and one communal roost that hosted 40 vultures of different ages. A (probable) singe adult bird at the breeding site was located and a previously occupied site was also visited. A preliminary survey amongst local people indicated that threats faced by this species are predator poisoning in some areas, and the use of vulture parts for traditional medicine. Given that the species is considered globally Endangered and populations continue to decline in many areas, the discovered population reported here, although relatively small, is of national and regional (North-west Africa) importance. We expect this new situation will revive the hopes for studying and conserving this and other vulture species in Morocco and North-west Africa in general.     

Nesting habitat preference of the African White-backed Vulture Gyps africanus and the effects of anthropogenic disturbance

The African White-backed Vulture Gyps africanus is widely distributed across sub-Saharan Africa but populations are in decline. Loss of suitable habitat for foraging and breeding are among the most important causes, and future conservation will require identification of suitable remaining habitat and the threats to it and to the vultures in it. Like many large raptors, African White-backed Vultures have a long breeding cycle and thus spend much of each year near their nest site, but ecological correlates of nest sites have not been quantified for any African vulture species. We use nest-site data for African White-backed Vultures collected during aerial and ground surveys and habitat data derived from a GIS to develop statistical models that estimate the probability of nest presence in relation to habitat characteristics, and test these models against an independent dataset. The models predicted that both direct and indirect disturbance by humans limit the potential distribution. Suitable habitat needs to be identified and receive adequate protection from poaching. Poaching of vultures is thought to be mainly for use in traditional medicine and does not target any particular species, so all vulture species can be considered equally at risk. We predict the likelihood of individuals nesting in currently unprotected areas should they become protected. These predictions show that readily available GIS data combined with relatively simple statistical modelling can provide meaningful large-scale predictions of habitat availability.     

Do Power Lines and Protected Areas Present a Catch-22 Situation for Cape Vultures (Gyps coprotheres)?

Cape vulture Gyps coprotheres populations have declined across their range due to multiple anthropogenic threats. Their susceptibility to fatal collisions with the expanding power line network and the prevalence of carcasses contaminated with illegal poisons and other threats outside protected areas are thought to be the primary drivers of declines in southern Africa. We used GPS-GSM units to track the movements and delineate the home ranges of five adult (mean ±SD minimum convex polygon area  =  121,655±90,845 km²) and four immature (mean ±SD minimum convex polygon area  =  492,300±259,427 km²) Cape vultures to investigate the influence of power lines and their use of protected areas. The vultures travelled more than 1,000 km from the capture site and collectively entered five different countries in southern Africa. Their movement patterns and core foraging ranges were closely associated with the spatial distribution of transmission power lines and we present evidence that the construction of power lines has allowed the species to extend its range to areas previously devoid of suitable perches. The distribution of locations of known Cape vulture mortalities caused by interactions with power lines corresponded to the core ranges of the tracked vultures. Although some of the vultures regularly roosted at breeding colonies located inside protected areas the majority of foraging activity took place on unprotected farmland. Their ability to travel vast distances very quickly and the high proportion of time they spend in the vicinity of power lines and outside protected areas make Cape vultures especially vulnerable to negative interactions with the expanding power line network and the full range of threats across the region. Co-ordinated cross-border conservation strategies beyond the protected area network will therefore be necessary to ensure the future survival of threatened vultures in Africa.     

Breeding of the lappet-faced and white-headed vultures (Torgos tracheliotus Forster and Trigonoceps occipitalis Burchell) on the Serengeti Plains, Tanzania

The lappet-faced and white-headed vulture nests in a 1636 km² study area on the Serengeti Plains were kept under observation from June 1972 to August 1973. Active nests were inspected from a light aircraft at intervals of approximately 2 weeks. The inverse nesting densities were estimated as 43 km²/pair for the lappet-faced vulture and 409 km²/pair for the white-headed vulture. Nests were built of sticks in exposed sites on the crowns of trees, Acacia tortilis being the most popular species. Where the previous history was known, 44% of lappet-faced vulture nests were newly constructed, and the rest re-used from the previous year. The incubation period was about 55 days and the fledging period about 100 days in both species. Juveniles continued to frequent their nests after they could fly, sometimes for several months. Most lappet-faced vultures laid their eggs in April-May, the white-headed vultures in June-August. This means that the lappet-faced vultures raised their young during the dry season, when Grant's and Thomson's gazelles were the only animals present in any numbers on the plains. By contrast, the Ruppell's griffons nesting in the nearby Gol Escarpment colony raise their young during February-May, when the wildebeest and zebra herds are normally on the plains. The survival rate of lappet-faced vultures from laying to fledging was about 40%. The chicks are thought to be vulnerable to predation by tawny eagles, and one was known to have been killed by a leopard. Three adult vultures were killed on their nests, from unknown causes. Food remains from lappet-faced vulture nests showed a heavy preponderance of Grant's and Thomson's gazelles in all cases, with golden jackal the next most commonly occurring species. No food remains were obtained from white-headed vulture nests. The possibility of using aerial counts of vulture nests as an indicator of productivity is discussed.     

Modelling species distributions to predict areas at risk of invasion by the exotic aquatic New Zealand mudsnail Potamopyrgus antipodarum (Gray 1843)

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Declines in scavenging by endangered vultures in the Horn of Africa

Scavenging is an important ecological process. By quickly locating and consuming carrion, vertebrate scavengers cycle nutrients, stabilize food webs, and may help mitigate disease transmission to humans. Across Africa, many scavengers feed at abattoirs (i.e. slaughterhouses), thereby aiding in waste removal. Little information exists on the scavenger community composition and dynamics at abattoirs, and, to our knowledge, the carrion removal that scavengers provide at these sites has never been quantified. We studied vertebrate scavenger ecology at 6 abattoirs in Ethiopia with time-lapse photography and in-person surveys from 2014–2019. Specifically, we investigated daily, seasonal, and inter-annual patterns in use of abattoirs by vertebrate scavengers and estimated carrion consumption rates. We demonstrated the importance of abattoirs for supporting a large number and diversity of scavenger species, including 3 critically endangered, 2 endangered, 1 vulnerable, and 2 regionally endemic bird species. At the start of the study, vultures contributed 57% of carrion removal provided by vertebrate scavengers. Detections of critically endangered Rüppell's (Gyps rueppelli) and white-backed (G. africanus) vultures declined by 73% and critically endangered hooded vultures (Necrosyrtes monachus) declined by 15% over the study period. Simultaneously, the detections of dogs more than doubled. Using estimates of species-specific carrion consumption rates from the literature, coupled with changes in scavenger detections in our study, we estimated a 12% (54 kg/day) reduction in carrion consumption, or nearly 20,000 kg carrion less consumed per year by the end of the study at these 6 abattoirs. Our results indicate that ongoing vulture declines across Africa could significantly reduce carrion removal. We recommend that improving fencing around abattoir facilities could help restrict access by feral dogs, increase foraging by vultures, and, therefore, increase overall carrion removal rates.     

Toxicity of non-steroidal anti-inflammatory drugs to Gyps vultures: a new threat from ketoprofen

Three Gyps vulture species are on the brink of extinction in South Asia owing to the veterinary non-steroidal anti-inflammatory drug (NSAID) diclofenac. Carcasses of domesticated ungulates are the main food source for Asia''s vultures and birds die from kidney failure after consuming diclofenac-contaminated tissues. Here, we report on the safety testing of the NSAID ketoprofen, which was not reported to cause mortality in clinical treatment of scavenging birds and is rapidly eliminated from livestock tissues. Safety testing was undertaken using captive non-releasable Cape griffon vultures (Gyps coprotheres) and wild-caught African white-backed vultures (G. africanus), both previously identified as susceptible to diclofenac and suitable surrogates. Ketoprofen doses ranged from 0.5 to 5 mg kg⁻¹ vulture body weight, based upon recommended veterinary guidelines and maximum levels of exposure for wild vultures (estimated as 1.54 mg kg⁻¹). Doses were administered by oral gavage or through feeding tissues from cattle dosed with ketoprofen at 6 mg kg⁻¹ cattle body weight, before slaughter. Mortalities occurred at dose levels of 1.5 and 5 mg kg⁻¹ vulture body weight (within the range recommended for clinical treatment) with the same clinical signs as observed for diclofenac. Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies. Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in other regions of the world where vultures access livestock carcasses. The only alternative to diclofenac that should be promoted as safe for vultures is the NSAID meloxicam.     

When hunting benefits raptors: a case study of game species and vultures

Management of hunting activity to serve as a tool for sustainable development has become a key issue in conservation biology. However, little evidence is available showing positive impacts of hunting on ecosystem conservation, limiting its capability to be used as a conservation tool. We analysed hunting and its positive influence on the ecology and conservation of the griffon vulture (Gyps fulvus), a scavenger with a relevant function in the ecosystem, in the Cantabrian Mountains, NW Spain. Use of the area by vultures was addressed by looking for cliffs used as roosts or colonies, and consumption of game species by vultures was evaluated through field surveys and questionnaires to hunters. Results revealed a strong spatiotemporal adjustment in the use of the area by vultures and hunting events, especially of red deer and wild boar. Vultures occupied roosting sites very close to the main hunting sectors of these game species and often were seen consuming their carcasses. The spatiotemporal pattern of roost use by vultures strongly overlapped with hunting of red deer. The numbers of both red deer and wild boar hunting episodes within 3.5 km around the roosts were the best predictors of vulture occurrence and number. Our estimates show that hunting could feed around 1,800 vultures/6 months. Hunting can thus influence species at the top of the ecosystem (scavengers) and could aid sustainable management of griffon vulture populations, reconciling hunting and conservation. However, negative and positive impacts should be taken into account simultaneously for an overall evaluation of hunting on ecosystem conservation.     

Nesting distribution of vultures in relation to land use in Swaziland

Three species of vulture (African White-backed, White-headed and Lappet-faced) breed in Swaziland, all of which are threatened within the country. Vulture nests were surveyed using a fix-winged aircraft in low-lying savannas of Swaziland. Nesting was observed in three land use categories: (1) unprotected government cattle ranches, (2) protected cattle ranches, and (3) conservation areas. A total of 248 nests was recorded, of which 240 belonged to the African White-backed Vulture. Nesting densities were highest in conservation areas, an order of magnitude lower on protected cattle ranches and negligible on government ranches. Nests of White-headed Vultures and Lappet-faced Vultures were exclusively located in conservation areas. Nesting densities of African White-backed Vultures in some conservation areas exceeded 260 nests/100 km², which are the highest known densities of this species anywhere in Africa. Nests were almost exclusively located in riparian vegetation, but at Hlane National Park a large proportion of nests were placed in open woodland, possibly as a result of an influx of vultures from adjoining agricultural lands that have only been transformed in recent decades. Where elephants were present in conservation areas, vultures did not nest within their enclosures. The location and density of vulture nests may possibly be used as an indicator of pressure on biological resources in low-lying savannas of Swaziland.     

Pyrimethamine–sulfadoxine resistance in Plasmodium falciparum: what next?

Chemotherapy remains the only practicable tool to control falciparum malaria in sub-Saharan Africa, where >90% of the world's burden of malaria mortality and morbidity occurs. Resistance is rapidly eroding the efficacy of chloroquine, and the combination pyrimethamine–sulfadoxine is the most commonly chosen alternative. Resistant populations of Plasmodium falciparum were selected extremely rapidly in Southeast Asia and South America. If this happens in sub-Saharan Africa, it will be a public health disaster because no inexpensive alternative is currently available. This article reviews the molecular mechanisms of this resistance and discusses how to extend the therapeutic life of antifolate drugs.     

A new Old World vulture (Falconiformes: Accipitridae) from the Miocene of Gansu Province, northwest China

A large-sized and almost complete fossil vulture was discovered from the Late Miocene Liushu Formation of Linxia Basin in northwestern China. It is the best-preserved and the most complete fossil vulture yet discovered. The new genus and species Gansugyps linxiaensis is proposed and assigned to the family Accipitridae; morphology and limb proportions suggest it was chiefly an arboreal and soaring bird. It is more advanced than the other two known Miocene vultures from China. This new fossil increases our knowledge of the evolutionary history of vultures, and has implications for reconstructing the paleoecology of this region.     

Communal farmers of Namibia appreciate vultures and the ecosystem services they provide

Ecosystem services are cited as one of the many reasons for conserving declining vulture populations in Africa. We aimed to explore how communal farmers in Namibia perceive vultures and the ecosystem services they provide, with special focus on cultural and regulating ecosystem services. We surveyed 361 households across Namibia’s communal farmlands and found that over two-thirds of households liked vultures and found them useful, stating that they were harmless and useful for locating dead livestock. The minority of households who disliked vultures believed that they were killing their livestock. Poisoning was the main cause of vulture mortalities reported by farmers. While poisoning appears to be a concern for vultures in the communal farmlands, it appears that cultural use of vulture body parts is a minimal threat. We found that few farmers knew of cultural beliefs about vultures or uses for body parts; most farmers believed these beliefs and practices to be outdated. It is further promising that communal farmers have an overall positive perception of vultures. This highlights the potential for communal conservancies to bring attention to vulture conservation in their constituencies.     

Persistent organochlorine pesticides detected in blood and tissue samples of vultures from different localities in South Africa

Gaschromatography was used to establish the presence of quantifiable residues of 14 persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver and muscle samples obtained from individual African whitebacked (Pseudogyps africanus), Cape griffon (Gyps coprotheres) and Lappetfaced (Torgos tracheliotos) vultures from different localities in South Africa. The levels of pesticides measured in whole blood samples of live specimens were compared between nestlings from two natural breeding colonies, adults from a wildlife area and birds held in captivity. Statistically significant (P<0.05) differences between populations were detected in geometric means calculated for γ-BHC (lindane), α(cis)-chlordane and α-endosulfan. Five of the organochlorine contaminants displayed significant variations between concentrations detected in the clotted blood, organs and muscles excised from vulture carcasses. This includes residues of γ-BHC, α-chlordane, dieldrin, β-endosulfan and heptachlor epoxide. Values of the respective biocides measured in vulture samples were generally low in comparison to results documented for a number of avian species. Although no threat is posed by any of the organochloride pesticides, continual monitoring of especially breeding colonies is recommended. Furthermore, the suitability of African whitebacked vulture nestlings as basic bioindicators is highly advocated.     

Evidence that vulture restaurants increase the local abundance of mammalian carnivores in South Africa

Vulture restaurants are used worldwide as a conservation tool to provide threatened vultures with a source of supplementary carrion free from anthropogenic contaminants such as poisons and veterinary drugs. While the impacts of supplementary feeding sites on ecosystem and scavenging community dynamics have been investigated in Europe, no information is currently available for southern Africa. This study presents evidence that providing supplementary carrion for vultures stimulated an increase in local abundance of two species of mammalian carnivores, the brown hyaena (Hyaena brunnea) and the black‐backed jackal (Canis mesomelas). These findings require that the wider impacts of providing supplementary carrion for conserving threatened species are fully investigated.     

Global diversity of rotifers (Rotifera) in freshwater

Rotifera is a Phylum of primary freshwater Metazoa containing two major groups: the heterogonic Monogononta and the exclusively parthenogenetic Bdelloidea. Monogononta contains 1,570 species-level taxa, of which a majority (1,488) are free-living fresh or inland water taxa. Bdelloidea contains 461 “species,” only one of which is marine, but with many limnoterrestrial representatives or animals of unknown ecology. Actual numbers may be much higher, considering the occurrence of cryptic speciation in Monogononta and the unsatisfactory nature of taxonomic knowledge. Rotifers, mostly monogononts, occur in all types of water bodies, worldwide. They are particularly diverse in the littoral zone of stagnant waterbodies with soft, slightly acidic water and under oligo- to mesotrophic conditions. The rotifer record is highest in the Northern hemisphere, which may be due to the concentration of studies in those regions. Diversity is highest in the (sub)tropics; hotspots are northeast North America, tropical South America, Southeast Asia, Australia, and Lake Baikal, endemicity is low in Africa (including Madagascar), Europe, the Indian subcontinent, and Antarctica. Although the lack of fossil evidence and of molecular phylogenetic studies are major hindrances, contrasting hypotheses on the origin and evolutionary history of Brachionus, Macrochaetus, and Trichocerca are presented. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment