Rationale (Changed due to Change in criteria)

The regional population of White-backed Vulture Gyps africanus satisfies criterion A4 (a population size reduction of 80%, projected or suspected to be met within a three generation period including the past and future, based on actual or potential levels of exploitation). A recent apparent escalation of large-scale poisoning incidents throughout the broader southern African range of the species, motivated by the masking of poaching operations and harvesting for the traditional health industry are the main drivers in this regard as are interactions with power-lines.

Distribution

The White-backed Vulture is widespread in Africa south of the Sahel zone, with the exception of heavily forested equatorial regions in West and Central Africa (BirdLife International 2014). Within the region it occurs in the northern parts of South Africa and in eastern Swaziland (Mundy 1997). In South Africa, it is only absent from two of the nine provinces, i.e. Western Cape and Eastern Cape provinces, and from Lesotho. There is no evidence from the historical record that it ever bred in these three regions (Boshoff et al. 1983, Bonde 1993). It is now only a non-breeding visitor to Gauteng (Whittington-Jones 2004), although it bred there in historical times, e.g. at Hammans­kraal and Zoutpan (Tarboton and Allan 1984).

Although the overall distribution as shown in SABAP1 was not considered to have changed significantly from earlier times, there was evidence for marked decreases in parts of the range (Tarboton and Allan 1984, Mundy 1997). The overall distribution in the region also appears similar between SABAP1 and SABAP2. There is a suggestion of reduced abundance between the two atlasing periods, however, along the southern edge of the range in the Northern Cape and North West provinces (and possibly in the adjacent Free State), except in the Kimberley area where the population seems more isolated in SABAP2 compared with SABAP1. By contrast, SABAP2 shows records from further west in KwaZulu-Natal than did SABAP1.

Habitat View more ecological information

Population

The total southern Africa population was estimated at 15 000 pairs or 40 000 individuals in the mid-1990s and the global population at 270 000 mature individuals in the early 1990s (Mundy et al. 1992). These estimates, now approaching or over 20 years old, require updating.

In the region covered by the former Transvaal province of South Africa, the White-backed Vulture's breeding population in the late 1970s was estimated at 2 500 breeding pairs, of which 1 404 were in the Kruger National Park, 246 were in the Adjacent Private Nature Reserves, 630 were in the western Limpopo basin and 220 were in other regions of that erstwhile province (Tarboton and Allan 1984). Herholdt et al. (1997) estimated the Kruger National Park population at 600-1 000 pairs in the mid-1990s. Recent (2011) estimates for the Kruger National Park population are 624 pairs (Monadjem et al. 2013) and 904 (95% CI ±162) pairs (Murn et al. 2013), although both estimates apparently derive from the same dataset. Of these two estimates, the latter is likely the more applicable as it derives from a study specifically aimed at estimating population sizes. Murn et al. (2013) suggested that the population in the Kruger National Park may have decreased by as much as 50% since the late 1970s, mainly due to poisoning, although the difference between the late 1970s estimate and their estimate is 36%. An even more recent (2012) count of the area corresponding with Tarboton and Allan's (1984) ‘western Limpopo basin' region suggested a population of 610 pairs (480 active, and 130 inactive, nests), a figure remarkably similar to the earlier count. The breeding population in North West, now encompassing the south-western portion of the former Transvaal, allegedly may have been ‘well over 500 pairs' in the late 1990s (Verdoorn 1997, 2004). Specific breeding localities mentioned include Wolmaransstad, Christiana, Bloemhof, Klerksdorp, Zeerust, Mmabatho, Mafikeng, Vryburg, Stella, Madikwe and Molopo, with at least 100 pairs in the last-mentioned region, but exact details are lacking.

In Free State province, the species has been recorded breeding since the mid-1980s at 12 localities, all in Kalahari Thornveld areas in the north-east of the province, and the population in the late 1990s ‘may be over 100 pairs' (Colahan and Esterhuizen 1997). A similar number was estimated in 2001, although it was believed that the population in the Sandveld Nature Reserve had decreased (Colahan 2004).

In Northern Cape Province, the population in the late 1990s was estimated at a maximum of 300 pairs (Anderson and Maritz 1997) but this was subsequently revised to at least 500 pairs (Anderson 2004). Breeding occurs at four main nodes: the greater Kimberley area, Askam (c. 100 pairs), the South African portion of the Kgalagadi Transfrontier Park, and Breipal near Vanzylsrus. The greater Kimberley population was thought to number c. 107 pairs in the late 1990s (Anderson and Maritz 1997) but in 2001 this population was counted in greater detail and 244 breeding pairs were located at six different localities: Dronfield 43 pairs; Riet River 69 pairs; Rivermead 24 pairs; Susanna 79 pairs; Paardeberg 27 pairs; and Secretarius 2 pairs (Murn et al. 2002). Of these six localities, the Susanna colony occurs in the Free State Province and the Dronfield colony straddles both the Northern Cape and Free State provinces. The Kgalagadi Transfrontier Park population was estimated at c. 60 pairs in the late 1990s but earlier work during 1988-1990, however, stated that only a maximum of 25 breeding pairs was found in this protected area and that there was evidence of population reduction related to poisoning on neighbouring commercial farms (Herholdt and Anderson 2006). The Breipal population near Vanzylsrus was established in 1999, numbered c. 100 pairs in 2003 and apparently over 200 pairs in 2008 (Anderson and Maritz 1997, Anderson 2004, Maritz 2008).

In KwaZulu-Natal, 103 and 106 occupied nests were counted in Hluhluwe-iMfolozi Park in 1972 and 1973 respectively (Hitchins 1980). In 1984, 242 occupied nests were counted in Hluhluwe-iMfolozi Park and the increase was ascribed to immigration related to the loss of suitable nesting sites outside the protected area (Whateley 1986). One estimate of the total KwaZulu-Natal population in the late 1990s was 350 pairs (Piper and Johnson 1997). Another covering the same period, however, estimated the population in the KwaZulu-Natal ‘Important Bird Areas' at 480-545 pairs (Ndumo 50-60 pairs, Itala 10-15 pairs, Mkuze 200 pairs, HIP 200-250 pairs; (Johnson et al. 1998). Unfortunately, this estimate provided no supporting details and assumed that breeding occurred at several localities which subsequent investigations showed to be incorrect, e.g. Ndumo, Ithala and ‘St Lucia' (Rushworth et al. 2007, Howells et al. 2011) An estimate for 2004 was 300-350 pairs in KwaZulu-Natal, with 150-250 pairs in protected areas, and the population was believed to be decreasing (Rushworth and Piper 2004). In 2007 and based on aerial surveys, the KZN population was estimated at 344 pairs, 275 in HIP, 35 in Mkuze Game Reserve and 34 in Pongolo Nature Reserve (McKean et al. 2013). During a 2011 aerial survey, 418 occupied nests were counted in HIP (Howells et al. 2011). The 2011 aerial survey also covered the other main breeding localities of this species in Zululand and counted 14 pairs at Mkuze Game Reserve, which has decreased further to 8 pairs in 2013, 22 at Pongolo Nature Reserve, 41 at Pongola Private Game Reserve, 32 at Thula Thula Private Nature Reserve and eight at Magudu South. This provided at total of 535 pairs in Zululand, i.e. essentially the province as a whole, of which 78% are in HIP.

In Swaziland, the breeding population was estimated at about 200 pairs in the early 1990s (Parker 1994, 1997). In 2001, Monadjem (2003) estimated the population at 163 pairs but subsequently considered this to have been an underestimate in the light of a comprehensive count of 240 active nests in 2002. These were located almost exclusively in protected areas, mainly at Hlane-Mlawula-Mbuluzi but also at Mkhaya-Big Bend and the IYSIS Cattle Ranch (Monadjem and Garcelon 2005). The species was believed to be increasing in Swaziland in 2003 (Monadjem et al. 2003).

Uneven coverage and the outdated nature of some estimates make an accurate current estimate of the total breeding population for the region uncertain. The best estimate would be about 3 675 breeding pairs (i.e. 7 350 mature individuals), i.e. Kruger National Park 904, remainder of region covered by former Transvaal 1 096, North West (excluding area previously in former Transvaal) 300, Free State 100, Northern Cape 500, Swaziland 240 and KwaZulu-Natal 535. This is similar in total to the 3 500 pairs estimated by Anderson (2000). It differs substantially in detail though, i.e. with fewer pairs estimated for the Kruger National Park and more pairs for Northern Cape, Swaziland and KwaZulu-Natal.

Population trend

Tarboton and Allan (1984) considered that ancestrally the White-backed Vulture was ‘undoubtedly more abundant and widely distributed' in the former Transvaal Province than it was in the late 1970s. They provide several examples of known breeding localities abandoned in the period from the beginning of the last century until the early 1970s, although they also cite two examples of new, albeit small, colonies established in the late 1970s, one linked to game farming, and the other to the establishment of a protected area. In the Satara region of Kruger National Park, 64-68 pairs were counted in 1967-68 (Kemp and Kemp 1975) but in 1979 only 33-44 pairs were found in the same area (Tarboton and Allan 1984). This represents a decrease of 33-50%, which was attributed to a prolonged drought prior to the earlier counts. As discussed above, the latest information from Kruger National Park suggests a possible 36% decrease in breeding pairs between the late 1970s and 2011 (Murn et al. 2013).

The White-backed Vulture also seems ancestrally to have been more widespread in Free State and Northern Cape provinces, and in Swaziland. In Free State, it may be continuing to decrease but specific details are lacking (Colahan and Esterhuizen 1997, Colahan 2004). In Northern Cape, it is believed to be increasing overall, with a new colony having established near Vanzylsrus and the greater Kimberley population expanding, although evidence of local (but possibly only temporary) decreases have been observed in the Kgalagadi Transfrontier Park (Anderson and Maritz 1997, Murn et al. 2002, Anderson 2004, Herholdt and Anderson 2006).

In KwaZulu-Natal there would appear to have been a startling increase in breeding pairs at HIP, the primary stronghold of the species in that province (Hitchins 1980, Whateley 1986, Howells et al. 2011). As also mentioned above, the SABAP2 (2007 to date) data suggest a western expansion in range in KwaZulu-Natal when compared with the SABAP1 (1981-1991) distribution. The Mkuze breeding population, however, was known to have decreased from 34 pairs in 2004 to eight pairs in 2009 in the face of several poisoning incidents, subsequently increasing marginally to 14 pairs in 2011 (Howells et al. 2011). In Swaziland, the numbers of breeding birds may have increased locally in recent times, e.g. the species did not breed at Mkhaya Game Reserve in the mid-1980s but 10-15 pairs nested there by the mid- to late-1990s (Monadjem et al. 2003).

The most parsimonious conclusion based on the available information would suggest that overall the White-backed Vulture population in the region has remained largely stable since about the 1970s, until the recent apparently large-scale decreases in the Kruger National Park and in the network of reserves in KwaZulu-Natal.

Threats

The primary threats to the White-backed Vulture are similar to those faced by the other large vulture species in the region and appear to stem at core from contamination (and at least sometimes perhaps shortage) of their food supply, negative interactions with human infrastructure, and demand for vultures for use in the traditional health industry. Threats reducing adult survival, as is the case relevant to many of the dangers discussed below, are of particular concern, as the population stability of this species, which evidences a naturally low reproductive rate, likely depends on high adult survival rates.

Poisoning as a major threat to this species has been exhaustively documented (van Jaarsveld 1986, Mundy et al. 1992, Anderson 1995, Herholdt and Anderson 2006, Botha 2007, Naidoo et al. 2011). This poisoning may be deliberate, e.g. when aimed at harvesting birds for the traditional health industry, or accidental, e.g. when targeting mammalian carnivores. A frightening recent development in southern Africa is the mass poisoning of vultures, primarily of this species, in the large protected area strongholds in Zimbabwe, Botswana and Namibia to help cover poaching activities, although the traditional health industry has also been implicated in at least some of these instances (Hancock 2009, Groom et al. 2013, Bradley and Maude 2014). The wide ranging nature of White-backed Vultures means that birds originating from the region could easily succumb to such incidents in the neighbouring states. Unconfirmed low levels of poisoning, likely with organophosphates, are suspected in many birds taken to animal rehabilitation centres (Naidoo et al. 2011). The non-steroidal anti-inflammatory drug (NSAID) diclofenac, a major potential threat to Gyps vultures, is not currently known to be widely used for veterinary purposes in the region, nor is it licensed for such use, but this drug has been confirmed to be toxic to this species (Green et al. 2004, Pain et al. 2008). Ketoprofen, another widely available NSAID, is also toxic to this vulture (Naidoo et al. 2009).

This vulture is a frequent victim of electrocution on smaller pylons (Anderson and Kruger 1995, van Rooyen 2000, Kruger et al. 2004). It also succumbs to collisions while in flight with overhead transmission lines (Anderson 2000, van Rooyen 2000, Naidoo et al. 2011). Such collisions are likely a major cause of injuries and affects 42% of birds presented at rehabilitation centres, as evidenced by soft tissue and skeletal damage (Naidoo et al. 2011).

White-backed Vultures are highly sought-after in the traditional medicine trade and this comprises a further major threat to the species with many birds killed using poisons and other means of hunting to satisfy this demand (Mander et al. 2007, Bamford et al. 2009a, McKean et al. 2013). Bush encroachment is a threat that may render woodlands too dense for the birds to either easily see or access carcasses but to a lesser degree than the Cape Vulture (Bamford et al. 2009b). This vulture is also sensitive to disturbance, especially when breeding, and this typically restricts nesting to protected, or at least sparsely populated, regions.

The species occasionally drowns in circular concrete farm reservoirs particularly in the drier western parts of the region (Knight 1987, Anderson 1995, Anderson et al. 1997, 1999, Herholdt and Anderson 2006) but apparently not to the same extent as the Cape Vulture. It has been suggested that poisoned vultures may be particularly prone to such drowning, as one symptom of the poisoning may be extreme thirst, and this potential association should be investigated.

White-backed Vultures are also sometimes killed in collisions with motor vehicles (Anderson 2000), particularly where carcasses occur on or close to roads. The vulture is also known to have collided with aircraft in flight. White-backed Vultures are occasionally vulnerable to being caught in gin traps (Anderson 2000). Osteodystrophy, as has been claimed for the Cape Vulture, has also been claimed for this species (Verdoorn et al. 1997, Naidoo et al. 2011) but requires confirmation.

The long-distance movements evidenced by this species (Oatley 1998, Monadjem et al. 2013, Phipps et al. 2013), perhaps especially juveniles and immatures, which are truly sub-continental in scale, mean that individuals are exposed to a wide range of threats during the course of their wanderings. Even birds present in large protected areas move outside these regions and hence within range of the many major dangers faced by the species. A simple example is of a bird ringed in a private nature reserve near Kimberley in Northern Cape and recovered poisoned in Namibia (Bridgeford 2001). The White-backed Vulture, like the Cape Vulture, benefits from a communal foraging system and any large-scale reduction in numbers could negatively impact the efficiency of this method of carcass location, with further negative consequences for the species (Dermody et al. 2011).

Conservation

Underway

The Vulture Study Group was established in 1977 with a mainly southern Africa focus (Mundy et al. 1992). This group is now essentially subsumed into the broader Bird of Prey Programme of the Endangered Wildlife Trust. The Endangered Wildlife Trust's current vulture research and conservation activities largely operate under the umbrella of the SASOL Vulture Monitoring Project. The Wildlife and Energy Programme of the Endangered Wildlife Trust is targeted at minimising the risk to wildlife posed by energy and communications infrastructure, including the dangers to large birds such as vultures stemming from electrocution by, and collisions with, such infrastructure (van Rooyen and Piper 1997, Jenkins et al. 2010). The Wildlife and Energy Programme's largest project is to administer a strategic partnership, formed in 1996, between the Endangered Wildlife Trust and Eskom, South Africa's national electricity provider. The Wildlife and Energy Partnership maintains a ‘Central Incident Register' of all bird mortality incidents related to electrical infrastructure, including those involving vultures. VulPro based in North West province is active in the rehabilitation of vultures. A recently established global organisation specifically relevant to vulture conservation is the IUCN Vulture Specialist Group formed in 2011. Vulture News, a journal dedicated to publishing information on vulture research and conservation efforts and which was initiated in 1979 by the Vulture Study Group, is now the journal of the IUCN Vulture Specialist Group. The International Vulture Awareness Day, the first Saturday in September every year, aims to increase conservation awareness. Ezemvelo KwaZulu-Natal Wildlife initiated annual Vulture Count Days on International Vulture Awareness Day from 2003.

Mundy (2000) suggested that successful vulture conservation measures, based on experience gained largely in South Africa, relied on three ‘simple' approaches: 1) active conservationists working directly with land-owners to educate the latter as to the threats faced by these birds; 2) the need for up-to-date research and monitoring information to inform conservation action; and 3) that approaches based on cooperation and partnership were more productive than those based on confrontation. Verdoorn et al. (1997) provides an overview of the strategy aimed at engendering a positive attitude amongst farming communities relevant to vultures.

A vulture conservation strategy for KwaZulu-Natal covering the 5-year period 2008-2012 was produced. An increase in game farming on commercial ranch-lands within the range of the species is likely to the advantage of this species (Murn and Anderson 2008). Ezemvelo KwaZulu-Natal Wildlife has implemented a formal monitoring plan for this species in the province of KwaZulu-Natal to determine population trends and breeding success as well as to determine age specific mortality rates. A Zululand Vulture Group has been established to co-ordinate vulture conservation interventions within the Zululand region of KwaZulu-Natal. It is comprised of representatives from Non-Governmental Organisations, private land-owners and Ezemvelo KwaZulu-Natal Wildlife.

An example of mitigation relevant to electrocution by pylons is the modification of these structures to reduce this risk (Northern Cape Raptor Conservation Forum 2006). Collisions can be mitigated for by line-marking and judicious routing of lines, although the value of the former remains largely untested and may be inherently limited in its effectiveness related to the biological attributes of flying vultures (Jenkins et al. 2010, Martin 2011, Martin et al. 2012). A detailed assessment of the use of vultures in traditional medicine in South Africa has recently been undertaken (Mander et al. 2007, McKean et al. 2013). The danger posed by drowning in circular farm reservoirs is relatively easily ameliorated by placing objects such as logs into such structures, carefully regulating their water-levels, completely covering them or providing alternative, more suitable, drinking structures to avoid these incidents (Anderson et al. 1997, 1999).

Supplementary feeding (‘vulture restaurants') is a widely implemented vulture conservation measure both in the region and elsewhere in the world (Butchart 1988, Brown 1990, van Rooyen and Vernon 1997, Anderson and Anthony 2006, Monadjem et al. 2012, Phipps et al. 2013). The primary potential value of these schemes is to address any food shortages and to provide uncontaminated food. Supplementary feeding may be particularly valuable in increasing the survival of juvenile vultures (Piper et al. 1999). A guide to the establishment and operation of supplementary feeding sites is available (Boshoff et al. 2011). A vulture restaurant monitoring protocol document also exists (Wolter et al. undated). A register of vulture restaurants is maintained by VulPro and is updated on a regular basis with the use of tracking data identifying new feeding sites followed by site visits to confirm. There are apparently some 124 currently active feeding sites in southern Africa (Wolter 2012). These feeding sites are often accompanied by hides that allow close-up viewing of the feeding vultures; direct exposure that helps engender appreciation of these birds.

The rescue, rehabilitation and release by recognised rehabilitation facilities of White-backed Vultures temporarily incapacitated by the various threats faced by the species is an increasingly important conservation measure (Verrynne 1997, Naidoo et al. 2011). It should be noted, however, that only 26% of White-backed Vultures entering such facilities are subsequently released. Key facilities recently involved in such rehabilitation work include VulPro (North West), and the African Bird of Prey Sanctuary (KwaZulu-Natal).

Proposed

The key conservation measures required focus primarily on the major threats stemming from poisoning, energy-related infrastructure, the traditional health industry, potential food shortages, drowning and negative perceptions and ignorance. The scourge of poisoning needs to be combatted by the rigorous investigation and prosecution of all such instances, as well as the maintenance of ongoing and high-profile education and publicity campaigns emphasising the causes and negative consequences of such incidents. The legal penalties need to be severe enough to act as material deterrents. The recent trend of the mass poisoning of vultures in conservation areas to mask poaching activities and for the traditional health industry requires particular ameliorative action. A move to lead-free ammunition should be considered where relevant. Careful monitoring of the potential use of diclofenac, and other non-steroidal anti-inflammatory drugs lethal to Gyps vultures, is required. Meloxicam has been shown to be non-toxic to Gyps vultures and exists as an alternative NSAID (Naidoo et al. 2008).

Additional effort is required to reduce electrocutions and collisions of White-backed Vultures related to power-line infrastructure. Existing pylons and overhead lines need to be replaced or retro-fitted, on a carefully prioritised basis, and new infrastructure needs to designed and routed, to minimise the risks from electrocution and collisions. All known structures causing fatalities should be replaced immediately and all lines causing collisions should be mitigated without further delay.

Relevant to the use of White-backed Vultures in the traditional health industry, an intervention strategy is required that addresses the following primary areas of action: a) reduce consumption/demand for vultures through an awareness-building campaign targeting public consumers and current roleplayers; b) change/create policy to improve regulation of the vulture trade; c) improve policing and enforcement for better regulation of the trade; d) improve understanding of the trade to allow more focused interventions, including more research and monitoring (Mander et al. 2007, McKean et al. 2013). McKean and Rushworth (2008) provide supplementary guidelines for interventions aimed at addressing the threat to vultures from traditional use. Firm steps must be maintained to confirm that the food provided at supplementary feeding sites is free from any toxins harmful to the birds. The relevant stakeholders need to be continually reminded of the threat to White-backed Vultures posed by drowning the farm reservoirs. Similar ongoing action is required to control the dangers from human disturbance at breeding colonies on private land.

Research

* Regular and accurate censuses of the number of breeding pairs of White-backed Vultures throughout their regional range are a high priority in order to monitor the population size and stability on an ongoing basis. This is best achieved using aerial censuses using fixed-wing aircraft or helicopters (Murn et al. 2002, Monadjem and Garcelon 2005, Howells et al. 2011, Murn et al. 2013). Such counts are already being undertaken on an annual basis in the KwaZulu-Natal protected areas where this species occurs (Howells et al. 2011).

* Satellite and GSM tracking of adults, immatures and juveniles is invaluable in determining movements and mortality factors (Wolter 2006, Bartels et al. 2007, Phipps et al. 2013). Ringing and patagial tagging (Botha 2007, Monadjem et al. 2012) can also provide information on movements and mortality but is likely less cost effective in this regard.

* More research is required on the ongoing impact of electrical infrastructure on White-backed Vulture populations in terms of electrocutions and collisions, and on the efficacy of mitigation measures.

* Foraging patterns and food supply, coupled with the actual and potential value of supplementary feeding schemes, are worthy of deeper investigation linked to tracking studies.

* Ongoing research is required relevant to the exploitation of this species in the traditional health industry (Mander et al. 2007, McKean et al. 2013).

* The issue of potential lead poisoning through bullets, and fragments of bullets, lodged in carcasses available to White-backed Vultures, especially at supplementary feeding sites, requires urgent investigation.

* Further investigation of the potential toxicity of additional non-steroidal anti-inflammatory drugs, and other pharmaceutical drugs used in the veterinary industry, is necessary.