| Lappet-Faced Vulture | |
| Aegypius tracheliotos | |
| Status: | Vulnerable |
| Range: | Namibia, Botswana, Swaziland, n South Africa, w Zimbabwe |
| Area of occupancy: | 335,232 km2 |
| Population estimate in Namibia: | 500 pairs |
| Population trend: | Suspected 10% decline |
| Habitat: | Arid savanna through to desert watercourses |
| Threats: | Poisons, drowning, muti-trade, nest disturbance |
Distribution and abundance
 Click to see distribution map |
Formerly a very widespread species throughout most arid areas of Africa, it occurs n into the Arabian Peninsula and Israel as far south as 29oS in the Northern Cape, South Africa (Mendelssohn 1986, Mundy et al. 1992). It is a relatively widespread species throughout Botswana, western (arid) parts of Zimbabwe, and in South Africa, it is concentrated in the Kruger National Park. Historically it was found in areas where it is now entirely absent in the southwestern Cape as far as the Cape Town area (Boshoff et al. 1983, Mundy et al. 1992). It is the only one of Namibia's six resident vultures that occurs scattered throughout the country at low density. Its cores of distribution are centred on the gravel plains in the n Namib-Naukluft Park, particularly in the ephemeral rivers and their tributaries; west of the great Escarpment in Cunene Province (former Damaraland and Kaokoveld), Etosha National Park and scattered through dry farmland with rainfall less than 400 mm in central, eastern and s Namibia (Mundy 1997). The bird breeds as far south as 28.5oS, 30 km n of the Orange River (Cunningham & Strauss 2004). It is rare but present in low numbers in the Caprivi (Mundy 1997). It occupies an area of 335,232 km2 of which 20% lies within protected areas such as the Namib-Naukluft and Etosha NPs (Jarvis et al. 2001).
Up to 60 pairs of Lappet-faced Vultures are known to breed in any one year in the Namib-Naukluft (Bridgeford 2003). Allowing for a non-breeding component of 23% of adults (based on the non-breeding component of eight large eagle species: Vernon 1984) the total estimated population of Namib-Naukluft Park is c 78 prs of a total estimate for Namibia of c 500 prs (Bridgeford 2003). For Africa as a whole, the Lappet-faced Vulture population is estimated at 8000 individuals (Mundy et al. 1992). The density of birds along the northern Tsondab River in the Namib-Naukluft Park is one of the highest on record at 21 active nests in 12-15 km of riverine woodland, not all of which are active at any one time; this density recorded in 1991 has dropped to about 9 active nests in the year 2000 (Bridgeford 2003). However, simultaneous monitoring on the gravel plains around Ganab (further north) indicates a general increase in nesting birds from 6 nests in 1994 to 16 in 1999 (Bridgeford 2003). Because this species is rain-sensitive in its breeding (see below) annual variation in breeding numbers is expected. However, the decline in numbers in the Tsondab River exceeds that expected from the higher rainfall in recent years (Bridgeford 2003).
Density estimates from other areas in the southern Namib and pro-Namib are from lowest to highest density: Ganab: 75 km2/pr; Saagberg: 70 km2/pr; Sukses: 17.3 km2/pr; Tsauchab River area: 16.4 km2/pr; Tsondab River area: 14.3 km2/pr (Bridgeford 2003).
Ecology
This is Africa's largest vulture, although not the heaviest, and it is often dominant at carcasses (Sauer 1973, Brown 1986, Mundy et al. 1992). Despite its size and dominance it appears to be cosmopolitan in its prey selection; remains at nests shows that it takes fairly small prey such as rabbits and hares, and suggestions exist that birds in fact perch hunt for live prey (P Mundy pers comm). This suggestion could not be corroborated by direct observation where lamb depredation is involved in Namibia - jackal predation was implicated in the case investigated (Cunningham & Cunningham 1999) - but eye witness accounts exist in South Africa (Maritz 1997, McCulloch in press).
Lappet-faced Vultures prefer to breed in trees in the dry rivers washes that flow from east to west across Namibia's vast gravel plains in the pro-Namib, and they are particularly fond of the mature Acacia erioloba trees that line the southern rivers Tsondab, Tsauchab (that flows into the famous Sossusvlei) and the Koichab in the far south. These trees are fed by underground water as some of these dry rivers do not flow annually. Nests are large structures used for many years in which 1 egg is laid on 97.8% of occasions. Two eggs have been recorded on six occasions always in the northern Namib-Naukluft Park (Clinning 1978, Bridgeford et al. 1995). The first record of two chicks being raised successfully (despite a large size difference in mass) was found in the same area of the Namib-Naukluft Park (Bridgeford et al. 1995). Birds begin egg-laying in April, peak in June (53% of 221 records: Brown & Clinning unpubl), and finish laying in September. First chicks appear in the nests in July (30 records: P Bridgeford unpubl).
Rainfall in these areas is very low (124 mm p.a.), temperatures are often high (35oC+). Ten years' monitoring of the populations in the Tsondab region revealed a significant inverse correlation between rainfall and number of nests started, and rainfall and breeding success (Bridgeford & Bridgeford 2003). When rainfall was low (minimum 61 mm for the year during the study period), greater mortality was presumed to occur in prey animals such as Ostrich Struthio cameleus, Oryx Oryx gazelle, Hartmann's Mountain Zebra Equs zebra hartmannae and domestic stock, providing increased food availability allowing vultures to breed. This close inverse correlation between rainfall and breeding output allowed Bridgeford & Bridgeford (2003) to distinguish whether the depressed breeding that followed the mass poisoning (1995) just outside the park, was due to poisoning or rainfall. The low (12 mm rainfall) suggested breeding should have been good, but low number of breeding pairs (8) indicated that poisons did indeed depress the breeding population below its normal levels. The subsequent year breeding returned to normal (Bridgeford & Bridgeford 2003).
Threats
Poisons and drowning are the main threats to Lappet-faced Vultures in southern Africa and Namibia. In southern Namibia where small stock farming is common, 77% of farmers admitted to using poisons in the mid 1980s, and Lappet-faced Vultures are very rare there with only 0.9 birds seen/1,000 km of road surveys. This compares with the similar rainfall area of the Pro-Namib where 4.3 vultures/1000 km of road survey were recorded, and few small-stock farmers occur (Brown 1986). Even birds in Namibia's parks are not immune to poisons because adults forage outside the park boundaries, and young birds often disperse there; of 324 birds ringed by P. Bridgeford up to the end of 2002, 11 recoveries have occurred on farmland between 20 and 410 km east or south east of their birth (and ringing) site within the Namib-Naukluft Park. A further 12 were recovered in or near their nest. Of the 11 recoveries from farmland, 6 were poisoned, and a further 3 were suspected to be poisoned (P Bridgeford unpubl). That poisoning has not abated is evidenced by C Clinning who ringed 143 nestlings in the same region 10 yr earlier; of the 5 recovered in the south of Namibia, 3 were killed by strychnine, one was caught in a gin trap and one was shot (Brown 1986). Of the total 650 recoveries recorded by Oatley et al. (1998) where cause of death was known, most (8) were poisoned. In the worst case of poisoning of its kind, 86 Lappet-faced Vultures and 8 White-backed Vultures were poisoned about 50 km north of the Namib-Naukluft Park northern border by a farmer complaining of Lappet faced Vultures killing and eating his Dorper lambs (Simmons 1995). He poisoned the vultures using a Carbomate ("blougif") and since at least 11 more Lappetfaced Vultures were killed in the same year, at least 55% of the Namib-Naukluft Park's population was estimated to have succumbed to poisons in 1995 (Simmons & Bridgeford 1997). Given these statistics it is likely that poisoning and its irresponsible use in problem animal (small carnivore) control is the single biggest killer of vultures in Namibia, now and in the mid 1980s (Brown 1986).
Drownings are less important as a mortality factor among Lappet-faced Vultures than among other vultures with just 3 incidents involving 3 birds, documented by Anderson et al. (1999).
The use of Lappet-faced Vulture parts in the muti trade is also documented (Cunningham 1990, Hengari et al. 2004), although some healers report that they avoid "black vultures". However, disturbance at nests is also known to cause nest abandonment and breeding failures (Steyn 1982). This is evidenced recently by road construction work on the road to Sossusvlei, near the Tsauchab River where 10 active nests have declined to 5 following construction activity (Bridgeford & Bridgeford 2003) and in the northern Namib Desert, regularly visited by tour guides, where a nest has been abandoned in the last few years (B Brell pers comm). The higher density of breeding pairs in regions furthest from human disturbed areas (eg Tsondabvlei) may be a consequence of the lower human traffic in the area.
The last in this long list of threats is from collisions and electrocution by power lines which is unrecorded in Namibia but is known to be a threat in South Africa (van Rooyen 2000).
Conservation status
This species is classified as Vulnerable because of a suspected decline in numbers by at least 10% in the last 3 generations through poisoning. This is based on a mass poisoning incident close to the Namib-Naukluft park (Simmons 1995) and other vultures poisoned in the same year. This represented more than half of the 78 pairs estimated in the entire Namib-Naukluft population (above) and possibly 10% of the entire Namibian population estimated at 500 pairs. An average of 31 vultures have been poisoned or drowned per year in Namibia over the last 7 years (Bridgeford & Simmons unpubl data, Bridgeford 2001, 2002, W. Versfeld pers comm), despite continuing and increasing media coverage, farmer awareness forums by three different organizations, and poison awareness campaigns through booklets and posters by NGOs such as the Vulture Study Group (P Bridgeford pers comm), NARREC (2003) and REST (M Diekmann pers comm). Together with drownings, shootings and trapping detailed above, and unnatural mortalities recorded for other scavenging species on Namibian farmlands (Brown 1991), this mortality rate may represent the tip of an iceberg of unnatural mortality (Brown 1986, Bridgeford 2001).
The species is listed as Vulnerable in South Africa's Red data book for the same reasons as detailed here - poisonings, shooting, - but also habitat destruction of breeding trees (Anderson 2000), which is less of a problem in Namibia. Globally they are rated as Vulnerable because of extinctions in Israel and parts of North Africa, and a declining population estimated at 1,000 pairs in southern Africa or 8,000 individuals globally (Stattersfield & Capper 2000). If these population estimates are correct, Namibia holds c 50% of the southern African population of the Lappet-faced Vulture. Only in Saudi Arabia is it known to be increasing, in some areas by threefold over previous estimates (Newton & Shobrak 1993). However West African populations are in serious decline (Rondeau & Thiollay 2004).
Actions
Decreasing the incidence of irresponsible poisons is the single most important action to prevent further population declines in all species of vulture. There are several ways of doing so. Poison collars filled with 1080 and fitted around the neck of sheep and designed to specifically target the carnivores that kill them, have proven unsuccessful in preventing poisoning of non-target species such as vultures (Gildenhuys & Brown 1991). This is because the collars are punctured in Namibia harsh and thorny environment and spread over the sheep when the vultures scavenge them.
There are opposing viewpoints on the way forward. One proposal is to ban completely the poisons used for killing small carnivores from the Namibian environment (Brown 2002). This view advocates that: (i) it sets a standard that using poisons for killing predators is unacceptable and not in the national interest; (ii) it will cause the thinking farmer to choose other, more environmentally friendly methods; and (iii) when poisons were banned in western Europe vulture populations showed a remarkable recovery.
The opposite view is that the total ban is (i) impractical (ii) threatens the agro-chemical industry and (iii) is too idealistic to work (Verdoorn & Komen 2002). Concentrating on stopping abuse and working with farmers to apply poisons responsibly, is seen as the only way forward. The objective facts show that awareness campaigns and farmer education programmes have not stemmed the tide of poisonings in Namibia, even in the 21st century, because poison abuse continues to kill Namibian vultures at a steady rate. The critical point is that 100% of farmers need to be convinced of the need for sound farming and poison-free methods. Because it is just 0.1% of the population that is responsible for the decline (Brown 2002), then awareness campaigns alone will probably never work. For this reason, the draft Parks & Wildlife Management Bill (2002) has now banned 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. The Egyptian Vulture and the Cape Vulture are Specially Protected Species under this Bill (requiring management plans and annual updates), but the Lappet faced Vulture is not. It does however enjoy normal protection from persecution under the same legislation.
Taxonomic Note
This species has recently been moved from the genus Torgos to Aegypius because it clusters with, and is a recent offshoot from, the Eurasian A monarchus (Cinereous Vulture) (Wink & Sauer-Gurth 2000).
From: Simmons RE & Brown CJ 2006. Birds to watch in Namibia: red, rare and endemic species. National Biodiversity Programme, Windhoek, Namibia
References
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