Archived 2011-2012 topics: White-backed Vulture (Gyps africanus) and Rueppell’s Vulture (Gyps rueppelli): request for information

Initial deadline for comments: 31 January 2012 [note that this has been moved back by about two months].

BirdLife species factsheets for White-backed Vulture and Rueppell’s Vulture

White-backed Vulture Gyps africanus and Rueppell’s Vulture Gyps rueppelli both have widespread ranges in sub-Saharan Africa, with G. rueppelli being more restricted to the north and east of this region, and G. africanus also ranging into southern Africa. Both species are listed as Near Threatened under criteria A2; A3; A4, on the basis that they are estimated or suspected to be undergoing moderately rapid population declines (20-29% over three generations, estimated to be 48 years in both species) owing to the threats of habitat loss, incidental poisoning, persecution, off-take for domestic and international trade, the loss of wild ungulates and possibly diclofenac poisoning.

Declines in G. africanus in West Africa have exceeded 90% (J.-M. Thiollay in litt. 2006), with declines also noted in Sudan (Nikolaus 2006) and Kenya (Virani in litt. 2006). Populations have apparently been stable in Tanzania (D. Peterson in litt. 2006) and in Ethiopia, according to Nikolaus (2006), although Ash and Atkins (2009) note anecdotal evidence that the species has declined there. The species is thought to have declined by c.10% in recent years in South Africa, Lesotho and Swaziland, although a range expansion was noted around Ladysmith in western KwaZulu-Natal in 2001-2002 (Hockey et al. 2005 and references therein).

Extremely rapid declines in West African populations of G. rueppelli have also been noted, although the species may be stable in The Gambia (J.-M. Thiollay in litt. 2006). During vehicle-based transect surveys in the Sahel zone of Mali and Niger by Thiollay (2006), G. rueppelli was not recorded, despite being common during equivalent surveys in the early 1970s, suggesting that the population has collapsed, although several incidental records are noted for Niger in 2004 and 2005. Significant declines also appear to have taken place elsewhere, including Sudan (Nikolaus 2006), Uganda (D. Pomeroy in litt. 2006), Kenya (M. Virani in litt. 2006) and Tanzania (J. Wolstencroft in litt. 2006). However, the species may be stable in Ethiopia (Nikolaus 2006).

A recent study involving the comparison of results from transect surveys conducted in and around Masai Mara National Reserve in 1976, 1988 and 2003-2005 lends support to the declines previously noted in Kenya (Virani et al. 2011). This study documented an apparent decline of c.52% over c.15 years in the numbers of Gyps vultures present during the ungulate migration season (Virani et al. 2011). In another study, carried out in central Kenya, an apparent decline of 69% was noted in the numbers of Gyps vultures between 2001 and 2003 (Ogada and Keesing 2010).

Assessing overall population trends in such widespread and mobile species is inherently problematic, and such species may also be prone to natural fluctuations in abundance. However, it remains necessary to evaluate whether the current listing of Near Threatened for G. africanus and G. rueppelli is likely to be correct. If evidence were to suggest an overall decline of at least 30% over 48 years in these species, then they may become eligible for uplisting to Vulnerable. Any evidence that strongly points towards a decline of at least 50% over 48 years would probably qualify them for uplisting to Endangered.

Further information is requested in order to assist with the assessment of these species’ threat status, with particular emphasis on their population trends.

References:

Ash, J. and Atkins, J. (2009) Birds of Ethiopia and Eritrea: an atlas of distribution. London, UK: Christopher Helm.

Hockey, P. A. R., Dean, W. R. J. and Ryan, P. G. (2005) Roberts birds of southern Africa. 7th edition. Cape Town, South Africa: Trustees of the John Voelcker Bird Book Fund.

Nikolaus, G. (2006) Commentary: where have the African vultures gone? Vulture News 55: 65-67.

Ogada, D. L. and Keesing, F. (2010) Decline of raptors over a three-year period in Laikipia, central Kenya. J. Raptor Res. 44: 129-135.

Thiollay, J.-M. (2006) Severe decline of large birds in the Northern Sahel of West Africa: a long-term assessment. Bird Conserv. Int. 16: 353-365.

Virani, M. Z., Kendall, C., Njoroge, P. and Thomsett, S. (2011) Major declines in the abundance of vultures and other scavenging raptors in and around the Masai Mara ecosystem, Kenya. Biological Conservation 144: 746-752.

Related posts:

  1. Himalayan Vulture (Gyps himalayensis): request for information
  2. Archived 2010-2011 topics: Hooded Vulture (Necrosyrtes monachus): request for information
  3. Archived 2011-2012 topics: Madagascar Fish-eagle (Haliaeetus vociferoides): request for information
  4. Archived 2011-2012 topics: Orange-breasted Falcon (Falco deiroleucus): request for information
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11 Responses to Archived 2011-2012 topics: White-backed Vulture (Gyps africanus) and Rueppell’s Vulture (Gyps rueppelli): request for information

  1. Abdi Jama says:

    Both species are on their last legs in Somaliland especially west 45E due to poisoning from ‘medications’ used on livestock like camels, sheep, goats and cattle.

    It’s a major surprise to see either bird in Somaliland any more when as late as 2002, they were quite common on trash and offal dumps around Hargeisa especially the africanus.

  2. Joe Taylor says:

    The following information regarding status of G. africanus in Ghana is extracted from a document sent by F. Dowsett-Lemaire on 12 October 2011:

    “Today the main population is in Mole N.P., with only one individual seen in Bui N.P. in 2005 (Dowsett-Lemaire & Dowsett 2010). At least 7 at Tumu in 1968-69 (Sutton 1970), but none seen anywhere in the north in the 2000s outside Mole.Was collected at Kete Kratchi in 1894 (Reichenow 1897) and was still common in the region in the 1950s, as 30-40 were seen at a carcass on the Bassa River in Feb 1956 (Lamm & Horwood 1958). We do not know when it disappeared from central Ghana, but none was ever reported from Digya N.P, the memory of some wildlife guards going back to the late 1980s. In the south, has apparently become extinct in Shai Hills W.R., where up to 20 or 30 individuals could be seen until at least 1973 (Grimes 1987); one pair was still present in 2005 (pers. obs.), but it has not been recorded since c. 2007 (W. Apraku et al.). A vagrant at Elmina on 17 Mar 1996 (B. Piot) and one drifting on the edge of Kakum on 5 Feb 2003 (R. Cruse) are the only other records we could trace. Historical and vagrant records shown as hollow squares . . . Is about extinct in Ghana outside Mole N.P. This reflects the general trend of sharp decreases in West Africa in the last 30 years (Thiollay 2006).”

  3. White-backed vultures have undergone a significant decline in Malawi. The Birds of Malawi (Dowsett and Dowsett-Lemaire) show them occurring in 30% (or 52) of the Atlas squares throughout the country. They have been wiped out in Kasungu and Liwonde National Parks, where the species was common before, through poisoning most likely – there is much ancedotal evidence. But large declines in wildlife and predator populations in these parks probably also played a role. Now they are only regularly recorded from Lengwe and Majete Parks in the south, and Nyika NP in the north. A single bird was recorded in Nkhotakota Wildlife Reserve (-12.83 34.16), by Ken Longden in 2010, where they have surprisingly not been seen before. I estimate that they occur in less than half of the sites that they are shown to occur in, in the Birds of Malawi.

  4. Joe Taylor says:

    The following comments were sent by Darcy Ogada on 17 November 2011:

    Concerning the present status of both of these species, I think we can say with certainty that both are declining and declines have been fairly rapid. Based on data from our work here declines have averaged 60% over the past 30 yrs. Poisoning incidents in the last decade have really taken a toll on both species.

  5. Rob Simmons says:

    From the Namibian Red data book – to be published in 2012:

    WHITE-BACKED VULTURE Near Threatened
    Gyps africanus

    Distribution and abundance Widespread throughout suitable woodland savannas of sub Saharan Africa, the White-backed Vulture is probably Africa’s most abundant vulture (Mundy et al. 1992). It is less widespread than the Lappet-faced Vulture but is almost certainly more abundant because of its colonial nature. African populations have been estimated at 270 000 individuals (Mundy et al. 1992) with c. 40 000 individuals (15%) in southern Africa (Anderson 2000, Anderson 2004). Its core areas are the Kruger NP, and the northern border of South Africa from the Northern Cape eastwards, most of Zimbabwe, Botswana and all but the un-treed areas of Namibia (Mundy 1997). Core areas in Namibia include Etosha NP and the Caprivi Strip, but it is still common throughout the central and southern parts of Namibia.
    There is one estimate of Namibian populations of 6000 prs (Simmons in Anderson 2004). Two comparisons using population densities from the former Transvaal (of 2600 prs in 400 QDS: Tarboton & Allan 1984, Harrison et al.1997) and Swaziland (300 prs in 24 QDS: Monadjem et al. 2003) suggest that Namibia’s population which occupies an area of 305 272 km2 (Jarvis et al. 2001) approximately 1.12 fold and 18.6 fold larger than the Transvaal and Swaziland populations, respectively, gives estimates for Namibia of about 2900 prs – 5600 prs. Using a factor of 2.7 to convert from prs to individuals (Mundy et al. 1992, Murn et al. 2002), gives an estimate of 7830- 15 050 birds for Namibia. Because Swaziland breeding colonies are known to be particularly dense (A Monadjem pers obs), the Namibian population probably lies towards the lower end of this range, approximately 10 000 birds or 25% of the southern Africa’s total population. This requires a more rigorous assessment and may prove higher than this figure suggests (D Joubert pers comm). One recent aerial survey indicates that a colony near the Waterberg Plateau occurred at a density of 3.8 nests/10 km2 (Doulton & Diekmann 2006), as predicted at the lower end of the breeding density found in Swaziland.
    Road counts in Etosha and other arid regions of Namibia varied from 0.1 birds/1000 km to 146 birds/1000 km driven (Jarvis et al. 2001), considerably higher than any of the other vultures.

    Ecology Prefers the drier tall-tree savannas of southern Africa, particularly in Botswana’s and Namibia’s Kalahari Sand and mopane woodland belts (Mundy 1997). In Namibia it is found most abundantly in Etosha and regions to the n-e where prey populations of large ungulates are intact in Etosha NP (Mundy 1997). The tallest trees are used for breeding and roosting purposes (Mundy et al. 1992). Breeding occurs in the winter with egg-laying recorded from March (1), April (8), May (6), June (21), July (11) (Brown & Clinning unpubl data). Additional breeding data is surprisingly non-existent for Namibia so success of colonies is unknown.
    Feeds by scavenging from carcasses of both large and small indigenous mammals and domestic livestock, and is most often seen feeding in large noisy flocks at large carcasses in protected areas or at vulture restaurants (Steyn 1982, Mundy et al. 1992).

    Threats Like other vultures this species suffers from continuous poisoning both in Namibia (Simmons & Bridgeford 1997, Bridgeford & Simmons unpubl) and elsewhere (Mundy et al. 1992, Anderson 2000). The poisoning rate for this species was 41 birds in the 7 yr period 1995-2001, second only to the Lappet-faced Vulture (Bridgeford & Simmons unpubl data). Poisoned birds are found from southern Namibia to areas just outside the Etosha and Waterberg Plateau parks. They include nestlings hatched inside the Etosha NP (T Osborne, W Versfeld, pers comm.). Curiously White-backed Vultures still occur in the small-stock farming areas in southern and central Namibia where poisoning of small carnivores is common (Brown 1988, Brown 1991). This suggests either (i) that poisoning alone is not responsible for population declines and other factors such as food resource levels explain the demise of other vultures (Boshoff & Vernon 1980, Anderson 2000) or (ii) poisoning is decreasing in Namibia (unlikely: Komen 2002) or (iii) this species is a prolific breeder and the sink areas are rapidly re-populated with recruits from source areas away from poisons.
    Of these a declining food base due to (i) overall degradation of the environment, (ii) bush encroachment over large parts of its stronghold in central and n Namibia (Mendelsohn et al. 2002) and (iii) a decline in prey base due to better or alternative farming methods is the most likely cause (Boshoff et al. 1997). Central farming land where this species is most widespread has changed shape over the last 100 year. For example farmed land has risen from 48 000 km2 in 1902 to (more-intensively) farmed agricultural land of 356 000 km2 in 2002. Areas in former Ovamboland where the bird almost certainly occurred 100 yrs ago have been almost completely cleared for crop cultivation (Mendelsohn et al. 2002), leaving few records of vultures over the last 20 years (Mundy 1997).
    Electrocutions are often mentioned as a major cause of the slow decline in this species (van Rooyen 2000), and Namibia has thousands of kilometers of powerlines that are unfriendly to vultures (Brown & Lawson 1989). Yet the evidence that lines actually kill a substantial number of birds here is scant. There are just two records of injury/electrocution from farms n-e of Windhoek (P Bridgeford unpubl data). The low frequency may arise because power lines are not systematically searched, or birds killed are missed because they are quickly scavenged. It is unlikely that vultures act differently in Namibia to South Africa, (although the density of power lines is higher in South Africa than Namibia: C van Rooyen pers comm) so we conclude that it is under-reported rather than a non-existent problem.
    A more recently identified potential problem for Gyps vultures is the use of drug Diclofenac. The use of this drug in India for the treatment of cattle has decimated vulture populations there (Oaks et al. 2004). Its apparent use in southern Africa by veterinarians (M Anderson pers comm) could be a minor threat if used unchecked. Its level of use is unknown however.
    Drowning in farm reservoirs is commonly reported in arid areas of South Africa (Anderson et al. 1999), where White-backed Vultures were ranked third among all species drowned. Several cases are known in Namibia (Bridgeford 2001, 2002, Bridgeford & Simmons unpubl data), but the level is probably low.
    Use by traditional healers of nestling or adult birds is probably high for this species in Namibia, with about 48% of 17 healers indicating they use body parts such as brain, skull, heart and eyes from birds that they kill themselves or obtain from birds that have been killed (Hengari et al. 2004). The number of birds actually taken per year has yet to be determined.
    While nest disturbance, cited as a problem in South Africa (M Anderson in litt), has not been reported as such in Namibia, the taking of nestlings and the high visibility of White-backed Vulture colonies makes them prime targets for disturbance.

    Conservation status This species is classified as Near Threatened because despite a suspected long term decline of 10-20% and degradation of prime habitat over the last 100 yrs, there is some evidence that birds are increasing outside Etosha NP boundaries (T Osborne in Anderson 2004) and from increasing numbers at vulture restaurants in the Waterberg area (M Diekmann pers obs). Outside Namibia populations or breeding areas have also increased on Zimbabwe’s highveld (P Mundy in Anderson 2004), in Swaziland (Monadjem et al. 2003) and in the Northern Cape, South Africa (Murn et al. 2002, Anderson 2004).
    It is not classified as globally threatened because of its wide distribution throughout Africa’s wooded savannas (Birdlife International 2004). In South Africa it is classified as Vulnerable based on a suspected 10% decline (Anderson 2000), probably also as a result of poisoning associated with problem animal control operations and harvesting for traditional medicines. It is given the same Near Threatened status in Swaziland as designated here (Monadjem et al. 2003).

    Actions Decreasing the incidence of poisoning is paramount in preventing further population declines in all species of vulture. There are several ways of doing so which are discussed under Lappet-faced Vulture. The draft Parks & Wildlife Management Bill (2002) will ban the use of poisons in predator control, and permits are required from the Ministry of Environment & Tourism for farmers to use poisons in exceptional cases. Networks of vulture restaurants in areas known to be impacted by poisons can alleviate the problem of contaminated foods but may make vultures too dependent on man-provisioned food.
    The extent of drowning in farm reservoirs should be investigated and education to alleviate this problem instigated by the Ministry of Environment and conservation organizations such as NARREC and REST.
    Knowledge of the breeding of this species is virtually unknown in Namibia, despite monitoring projects. However in 2003 and 2004, 66 nestlings were ringed in the Seeis, Hochveld and Steinhausen areas (P Bridgeford, D Hienrich unpubl data). Numerous other hunting farms in these central-east regions have informal restaurants supporting numerous breeding birds (P Bridgeford pers obs). Such data should be published and future monitoring should assess breeding densities and the success of pairs breeding in them. Future population estimates require breeding density estimates from several areas and the extent that poisoning actually impacts populations in Namibia. Research including regular surveys of power lines near vulture colonies is required to determine the extent of the vulture collision and electrocution problem. Liaison with Nampower officials who regularly fly these lines would assist logistically. Where problem lines are identified, appropriate modifications or mitigation measures must be enacted.

    Anderson MD 2000. African White-backed Vulture Gyps africanus. In: The Eskom Red Data Book of Birds of South Africa, Lesotho & Swaziland. Barnes, K.N. (ed.). BirdLife South Africa, Johannesburg.
    Anderson MD 2004 African White-backed Vulture Gyps africanus. In: Monadjem A, Anderson MD, Piper SE Boshoff A (eds). The Vultures of Southern Africa – Quo Vadis? Proceedings of a workshop on vulture research and conservation in southern Africa. pp 15-27. Birds of Prey Working Group, Endangered Wildlife Trust, Johannesburg, South Africa.
    Anderson MD, Maritz AWA, Oosthuysen E 2002. Raptors drowning in farm reservoirs in southern Africa. Ostrich 70: 139-144
    Barnes KN (ed) 2000.The Eskom Red data book of birds of South Africa, Lesotho and Swaziland.
    Birdlife International 2004 Threatened Birds of the World. CD-ROM Birdlife International, Cambridge.
    Boshoff AF, Vernon CJ 1980. The past and present distribution and status of the Cape Vulture in the Cape Province. Ostrich 51: 230-250.
    Boshoff AF, Anderson M, Borello W (eds) 1997. Vultures in the 21st Century. Pp 67-75 Vulture Study Group, Johannesburg
    Bridgeford P 2001 More vulture deaths in Namibia. Vulture News 44: 22-26..
    Bridgeford P 2002 Recent vulture mortalities in Namibia. Vulture News 46:38.
    Bridgeford P, Simmons RE unpublished data. Recent unnatural vulture deaths in Namibia.
    Brown CJ, Lawson JL 1989 Birds and electricity transmission lines in South West Africa/Namibia Madoqua 16: 59-67.
    Brown CJ 1988 Scavenging raptors on farms: what is their future? African Wildlife 42: 103-105.
    Brown CJ 1991. Declining Tawny and Martial Eagle populations on farmland in central Namibia. Biological Conservation 56: 49-62
    Brown CJ 2002 Poisons and scavengers – the right way forward! Lanioturdus 35: 3-6
    Diekmann, Maria Director REST. unpublished data and personal observation (rest@iway.na)
    Doulton H, Diekmann M 2006 Aerial survey of African White-backed Vulture nests on farmland around Waterberg, northern Namibia. Vulture News 54: 20-26.
    Gildenhuys SD Brown CJ 1991 Field trials on poison collars for mammalian predators in Namibia: their effects on birds of prey Gabar 6: 10-12
    Hengari GM, Cunningham PL, Adank W 2004 The use of vultures by traditional healers in Namibia Vulture News 50: 23 – 28.
    Jarvis A, Robertson AJ, Brown CJ, Simmons RE 2001. Namibian Avifaunal Database. National Biodiversity Programme, Ministry of Environment & Tourism, Windhoek.
    Joubert Dave, lecturer Polytechnic of Namibia (djoubert@polytechnic.edu.na)
    Komen L 2002. Poison use and abuse in livestock farming. Proceedings of workshop, NARREC, Windhoek (liz@narrec.schoolnet.na)
    Monadjem A, Boycott RC, Parker V, Culverwell J. 2003. Threatened vertebrates of Swaziland. Swaziland Red data book; fishes, amphibians, reptiles, birds and mammals. Ministry of Tourism, Environment & Communication. Mbabane.
    Mundy PJ, Butchart D, Ledger J, Piper SE 1992. The Vultures of Africa. Acorn and Russel Friedman Books, Halfway House, RSA
    Mundy PJ 1997. Whitebacked Vulture. In: Harrison JA, Allan DG, Underhill LG, Herremans M, Tree AJ, Parker V, Brown CJ (eds). The Atlas of Southern African Birds Vol 1: 160-161. BirdLife South Africa, Johannesburg.
    Murn C, Anderson MD, Anthony A 2002. Aerial survey of African White-backed Vulture colonies around Kimberley, Northern Cape and Free State Provinces, South Africa. SA J Wildlife Research 32: 145-152.
    Oaks JL, Gilbert M, Virani MZ, Watson RT, Meteyer CU, Rideout BA Shivaprasad HL Ahmed S, Chaudhry MJI, Arshad M, Mahmood S, Ali A, Khan AA 2004 Diclofenac residues as the cause of vulture population decline in Pakistan. Nature 427: 630-633
    Osborne, Tim Dr Ornithologist unpublished data (kori@iafrica.com.na)
    Simmons RE 1995. Mass poisoning of Lappetfaced Vultures in the Namib Desert. J African Raptor Biology 10:3.
    Simmons RE, Bridgeford P 1997. The status and conservation of vultures in Namibia. In: Boshoff AF Anderson MD, Borello WD (eds.). Vultures in the 21st Century. Pp 67-75 Vulture Study Group, Johannesburg
    Steyn P 1982 Birds of prey of southern Africa. David Phillip, Cape Town
    Van Rooyen CS 2000 An overview of vulture electrocutions in South Africa Vulture News 43: 5-22.
    Verdoorn G, Komen L 2002 Counterpoint from the Poison Working Group. Lanioturdus 35: 7-11.

    RE Simmons Reviewed by: MD Anderson
    D Joubert
    P Bridgeford

  6. Joe Taylor says:

    The following comments were sent by Phil Hall on 12 December 2011:

    There is every likelihood that both species have now been extirpated in Nigeria. There have been no sightings over the past year in the last stronghold of both species, Yankari Game Reserve, and nor have there been any sightings in any other part of the country. The widespread decline appears to be entirely attributable to the trade in vulture parts for traditional juju practices and there is every likelihood that the demand for vultures will lead to similar declines in all other countries in the West African subregion.

  7. R Buij says:

    In Cameroon declined 60% (Thiollay 2001) in 27 years (1973-2000); a larger decline of 97% was recorded in unprotected areas of central West Africa in 30-35 years since the late 1960s (Thiollay 2006). Repeated surveys of J-M Thiollay’s (2001) transects in Cameroon, in the former stronghold Sudan zone where mean relative abundance of 0.64 ind/100 km in dry season 2000; same transects between 2007-2010 using similar methods detected 0.14 ind/100 km, suggesting continued decline after 2000. The highest numbers in northern Cameroon on road surveys between 2006-2010 were recorded along the border with Chad on the Waza-Logone floodplain, where 37 individuals were observed in 2007, hereafter only smaller groups (1-10 ind.) despite frequent road counts throughout north Cameroon. Only small numbers in Waza N.P. (1-5 ind) between 2006-10, often with more numerous Rüppell’s. White-backed Vulture was “abundant or common” in northern Cameroon in the 1990s (Scholte 1998) and breeding in Waza and Kalamaloué N.P.s. Breeding recorded in woodland section of Waza N.P. in 2006 (pers. obs.), none in the area in 2009-10 despite intensive nest searches. Regular in Guinea savannas of Bénoué Ecosystem, but density low (0.8-1.7 ind/ 100 km); apparently more frequent on Adamaoua plateau in southern Cameroon where associated with cattle farms. Poaching for traditional medicine trade from Nigeria since late 1990s targeted both Gyps vultures in northern Cameroon (through poisoning of water holes, which remains common practice). White-backed were frequently trapped at nests near and inside Waza N.P. (multiple sources). More vulnerable to nest harvesting or disturbance by humans than Rüppell’s vulture, which breeds on inaccessible cliffs outside unprotected areas of northern Cameroon.

  8. R Buij says:

    The above concerns White-backed Vulture.

    Rüppell’s vulture:
    In Cameroon declined 87% (Thiollay 2001) in 27 years (1973-2000), comparable to the overall decline of 94% in central West Africa in 30-35 years (Thiollay 2006). Rüppell’s vultures were still recorded breeding between 2006-10 in the Mandara Mountains of Cameroon, along the border with Nigeria. Scattered colonies also in other sites throughout the Sudan zone of Cameroon, often close to human habitation (max 35 ind./colony). Colonies in accessible sites have disappeared, e.g. on the edge of Waza N.P. where colony of 20-30 pairs in 1993 (Scholte 1998). Although apparently affected as least as much as White-backed, numbers on road counts between 2006-2010 comparable to Thiollay’s (2001) counts in 2000. Rüppell’s vulture is targeted for trade like White-backed, but most remaining nest sites in Cameroon are on steep, inaccessible cliffs and livestock carcasses sufficiently common to possibly sustain a small population.

  9. Joe Taylor says:

    The following comments were received from Ann and Mike Scott on 23 January 2012:

    An observation: we have noticed an increase in numbers of both Lappet-faced Vultures and White-backed Vultures on NamibRand Nature Reserve (60 km south of Sesriem) in Namibia over the past few years (e.g. a group of 64 WBV and 8 LFV on 30/12/09 at -25.500137S 15.980352E; and a group of 48 LFV + 12 WBV on 25/11/11 at -24.924754S 15.959531E). This trend is thought to be associated with the recent increase in activities of predators (leopard, cheetah) and associated scavengers (hyaena and jackals) on the Reserve. As we are fairly close to the edge of the south-western range of WBV, this is encouraging; however no WBF nests as yet, and only a few LFV breeding records.

  10. Philip Hall says:

    There is every likelihood that both White-backed and Ruppell’s Vultures have been completely extirpated in Nigeria as well as Lappet-faced and White-headed. The last stronghold for all these species was in Yankari National Park but there has now been no records for the past 2 years. It appears that the decline has been caused by the huge demand for vultures in the juju markets in the SW of the country and this is even having an impact on vulture populations in neighbouring countries.

  11. Gyps vultures in East Africa

    Based on recent surveys, Gyps vultures have declined by 52% over the last 30 years in Masai Mara National Reserve, Kenya (Virani et al. 2011). Recent evidence from telemetry studies suggests that Masai Mara is an important habitat for vultures used by a wide-ranging population of Gyps vultures that concentrate in the area during the dry season every year, which is particularly worrisome given that declines seen during this season over the last 16 years were even higher (over 60%) (Virani et al. 2011). Thus declines seen in the Masai Mara study are likely representative of declines in Gyps populations ranging across East Africa from Southern Ethiopia to Southern Tanzania. Range size of African white-backed vultures in a recent study was up to 220,000 km2 (average approximately 55,000 km2) and was up to 600,000 km2 (average approximately 130,000 km2) for Ruppell’s vultures (Minimum Convex Polygon, Kendall and Virani, unpublished). Given that Mara-Serengeti protected area is only 25,000 km2 these wide-ranging species inevitably spend considerable amount of time outside protected areas, where they come into contact with human disturbance and poisoning. Both Gyps species range over a large area spending up to 30% of their foraging time outside protected areas (Kendall and Virani, unpublished). In East Africa, the primary issue is poisoning, which occurs primarily outside protected areas, and thus the large range sizes of these two vulture species puts them at significant risk (Ogada and Keesing 2010, Otieno et al. 2010, Kendall and Virani In press). Recent evidence from wing-tagging and telemetry studies suggests that annual mortality, primarily from incidental poisoning, can be as high as 25% for African white-backed vultures (Kendall and Virani In press). In addition, the ungulate wildlife populations on which these two obligate scavenging species rely have declined precipitously throughout East Africa, even in protected areas, further threatening the survival of these species (Western et al. 2009).

    Ruppell’s versus African white-backed vulture

    Unfortunately historical records for Ruppell’s vultures and African white-backed vultures in East Africa are limited and the current transect findings from Virani et al. (2011) are based on historic counts that did not differentiate between the two species. Thus from this data alone we are unable to assess whether declines have been shared equally by both species. Other circumstantial evidence suggests that African white-backed vultures may be at greater risk than Ruppell’s vultures, given that during a recent telemetry study where Ruppell’s, Lappet-faced, and African white-backed vultures were tagged, Lappet-faced and African white-backed vultures suffered significantly higher mortality rates than Ruppell’s (Kendall and Virani In press). In addition, changes in relative abundances of the two Gpys species at carcasses between the 1960s and 2000s show a doubling of Ruppell’s vulture and lowering of African white-backed vultures and suggest that African white-backed vultures in East Africa may have suffered greater declines that Ruppell’s vultures (Kendall et al. In review). African white-backed vultures may also be at greater risk due to differences in nesting and foraging behavior. In general, tree-nesting species like African white-backed vultures tend to be more susceptible to human disturbance than cliff-nesters like Ruppell’s vultures. Finally recent evidence from carcass experiments and transects suggests that African white-backed vultures may spend more time foraging in non-protected areas than Ruppell’s vultures and may thus be at greater risk of exposure to poisoned carrion (Kendall, unpublished data). In East Africa at least, it would thus appear that African white-backed vultures are at greater risk and may be declining faster than Ruppell’s vultures. However, it is worth noting that Ruppell’s global population is likely smaller than African white-backed vultures and more limited in total range, which may offset some of these differences (Mundy et al. 1992).

    Overall there is strong evidence that both species are declining rapidly, likely at a rate far exceeding 50% over the last 45 years with particularly rapid declines in the last decade, but that African white-backed vultures may have experienced greater declines and be at greater risk of future declines.

    KENDALL, C., and M. VIRANI. In press. Assessing mortality of african vultures using wing tags and GSM-GPS transmitters. Journal of Raptor Research.
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