Justification of Red List Category
This species has been uplisted to Critically Endangered. Recent data suggests the already small population is declining at an extremely rapid rate owing to a variety of threats including poisoning, persecution and ecosystem alterations. The species has a very small population and local extinctions may be accelerated by major poisoning events in isolated localised subpopulations.
An old estimate of 7,000-12,500 mature individuals was extrapolated from a number of regional estimates. This equates to 10,500-18,750 individuals in total. However, a new estimate of the global population suggests the population is much smaller, consisting of just 5,500 individuals (Murn et al. 2016). This equates to just 3,685 mature individuals here placed in the band 2,500-9,999 mature individuals.
The species is thought to be declining at an extremely rapid rate. Ogada et al. (2016) estimate a median decline of 96% (range: 73-98%) over three generations (45 years). The species has shown severe declines throughout its West African range (F. Dowsett-Lemaire in litt. 2006, J.M. Thiollay in litt. 2006) and also across southern Africa (Ferguson-Lees et al. 2001).
This species has an extremely large range in sub-Saharan Africa (from Senegal, Gambia and Guinea-Bissau disjunctly east to Eritrea, Ethiopia and Somalia, and south to easternmost South Africa and Swaziland), where it is uncommon, but generally widespread outside forested regions (Harrison et al. 1997). It has declined rapidly in parts of West Africa since the early 1940s (P. Hall in litt. 1999, J. M. Thiollay in litt. 2006, 2012), is declining in East Africa (Virani et al. 2011) and in southern Africa is now largely confined to protected areas. New data suggests the regional populations are now much smaller than was previously thought: 721 nests in East Africa; 548 nests in Central Africa; 468 nests in Southern Africa and 156 nests in West Africa (Murn et al. 2016). In Botswana only four nests were located during gyrocopter surveys of three Important Bird Areas during 2008 and the species has the lowest relative abundance of the vulture species recorded (Hancock 2008), while in Niger there are only four records since 1995, all in the Gadabeji area (J. Brouwer in litt. 2012). The species has probably declined in central Mozambique (Parker 2005a), where the population was estimated at 200 pairs (Parker 2005b), but the entire country now contains approximately 150 pairs (Murn et al. 2016). The largest protected area in South Africa contains approximately 50 nests (Murn et al. 2013, Murn and Botha in press), but the species is likely to disappear from the country in the near future should current levels of exploitation and other pressures continue (McKean et al. 2013). An extrapolated estimate of the global population suggested there were 2,600-4,700 pairs (7,000-12,500 mature individuals) (Mundy et al. 1992) however new data suggests the population is much smaller, at just 5,500 individuals (Murn et al. 2016).
It prefers mixed, dry woodland at low altitudes, avoiding semi-arid thornbelt areas (Mundy et al. 1992). It also occurs up to 4,000 m in Ethiopia, and perhaps 3,000 m in Kenya, and ranges across the thorny Acacia-dominated landscape of Botswana (Mundy et al. 1992). It generally avoids human habitation (Mundy et al. 1992). The species is thought to be a long-lived resident that maintains a territory (del Hoyo et al. 1994, Murn and Holloway 2014). It may generally fly lower than other vultures, and is often the first vulture species to arrive at carcasses (Mundy et al. 1992). While it is often found on the periphery of vulture congregations at large carcasses, it is also often found at small carcasses and is probably an occasional predator (Mundy et al. 1992, Murn 2014, F. Dowsett-Lemaire in litt. 2006). It nests and roosts in trees, most nests being in Acacia spp. or baobabs (Mundy et al. 1992). Clutch size is one, the egg being laid a couple of months after rains have finished and the dry season is underway (Mundy et al. 1992). Pairs that breed have a success rate of 65-75% (Hustler and Howells 1988, Murn and Holloway 2014), however, up to 61% of pairs do not attempt to breed each year (Mundy et al. 1992, del Hoyo et al. 1994), often due to the presence of a dependent chick from the previous breeding season (Murn and Holloway 2014).
Reductions in populations of medium-sized mammals and wild ungulates, as well as habitat conversion throughout its range best explain the current decline (Mundy et al. 1992, P. Hall in litt. 1999, R. Davies in litt. 2006). Additional threats include indirect poisoning (R. Davies in litt. 2006) at baits set to kill jackals in small-stock farming areas, and in East Africa at poisoned baits set for larger mammalian carnivores such as lions and hyenas (C. Kendall in litt. 2012), and, particularly in East Africa, secondary poisoning from carbofuran and other poisons (Otieno et al. 2010). Deliberate poisoning to prevent vultures drawing attention to poaching activities has also been documented (Roxburgh and McDougall 2012, Ogada et al. 2016). Exploitation for the international trade in raptors (N. Baker in litt. 2006) also poses a threat. In 2005, 30 individuals of this species were confiscated by the Italian authorities (F. Genero in litt. 2005).
The species is recorded in trade in West and Central Africa (Buij et al. 2015). In South Africa, this species is captured for use in traditional medicines (R. E. Simmons and C. J. Brown in litt. 2006) and in Zambia White-headed Vultures have apparently been intentionally killed for use in witchcraft (Roxburgh and McDougall 2012). Breeding birds may readily desert nests in areas of high human disturbance (R. E. Simmons and C. J. Brown in litt. 2006). The species is highly sensitive to land-use and is highly concentrated in protected areas (Hancock 2008). Potential introduction of the non-steroidal anti-inflammatory drug diclofenac, which is fatal to Gyps spp. when ingested at livestock carcasses may represent a potential future threat to the species, although livestock have not been recorded as a potential food source for this species (C. Murn in litt. 2016).
Conservation and Research Actions Underway
CITES Appendix II. This species currently occurs throughout much of southern and East Africa's protected areas network (F. Dowsett-Lemaire in litt. 2006, Murn et al. 2016). It is classified as Vulnerable in Naimbia (Simmons 2015), Critically Endangered in Uganda and South Africa, Lesotho and Swaziland (Allan 2015; WCS 2016). Individuals were marked with patagial tags in Fouta Djallon vulture sanctuary, Guinea, in 2007 to monitor movements and for a toxicological assessment of the vulture population of the park (Rondeau 2008). Additional studies to monitor the movement of individuals within and between protected areas is under way in South Africa (C. Murn in litt. 2016). In 2007, a survey began to establish the extent of diclofenac use for veterinary purposes in Tanzania (BirdLife International 2007), and in 2008 an awareness-raising campaign at a conference of the World Organisation for Animal Health in Senegal led to a resolution being adopted unanimously by more than 160 delegates to request Members to consider their national situation with the aim to seek measures to find solutions to the problems caused by the administration of diclofenac in livestock (Woodford et al. 2008). At the 2014 Conference of the Parties of the Convention on Migratory Species, a set of guidelines to address poisoning was formally adopted (Ogada et al. 2016). The Hawk Conservancy along with the Endangered Wildlife Trust are currently working on providing training and equipment for anti-poisoning teams so that field staff will have the skills and equipment to respond to a neutralise poisoned carcasses (C. Murn in litt. 2016). Ongoing monitoring occurs in South Africa, Botswana, Kenya and Tanzania (C. Kendall in litt. 2016).
Conservation and Research Actions Proposed
Carry out co-ordinated surveys throughout the range of this species to clarify its population size and trends. Continue to raise awareness about the impact of poisoning on this species (R. E. Simmons and C. J. Brown in litt. 2006), and attempt to reduce the human-wildlife conflict that motivated the poisoning of carrion (C. Kendall in litt. 2016). Enforce anti-poisoning legislation (R. E. Simmons and C. J. Brown in litt. 2006). Minimise disturbance at nests (C. Kendall in litt. 2012). Eliminate the veterinary use of diclofenac and other toxic drugs in Africa. Limit the use of lead based ammunition. Carry out education and awareness programmes, particularly targeted at farmers, to reduce persecution, unintentional poisoning and hunting for cultural reasons, and continue to carry out the deployment of anti-poisoning training and equipment (C. Murn in litt. 2016). Promote measures to join up isolated protected areas and where suitable consider translocating birds to expand the range of the species (Murn et al. 2016), and research the movement ecology of this species to determine the extent of movement between breeding populations (C. Murn in litt. 2016). A number of recommendations were produced at the 2012 Pan-Africa Vulture Summit (Botha et al. 2012, Ogada et al. 2016): 1) Regulate import, manufacture and sale of poisons; 2) Legislate and enforce measures to prosecute those involved in illegal killing and trade in vulture species; 3) Protect and effectively manage breeding sites; 4) Ensure new energy infrastructure is 'vulture-friendly' and modify existing unsafe infrastructure; 5) Support activities to conserve vulture populations, including research and outreach activities.
Mid-sized, chunky vulture with predominantly blackish and white plumage as an adult. Strong colourful bill and rear-peaked head. Ruffed white legs and belly separated from downy white head by its striking black breast. Black ruff.
Text account compilers
Bird, J., Butchart, S., Ekstrom, J., Evans, M., Harding, M., Martin, R, Pilgrim, J., Taylor, J., Symes, A., Ashpole, J & Westrip, J.
Baker, N., Barlow, C., Bowden, C., Brown, C., Davies, R., Dowsett, R., Dowsett-Lemaire, F., Genero, F., Hall, P., Ndang'ang'a, P., Pomeroy, D., Simmons, R., Thiollay, J., Wolstencroft, J., Brouwer, J., Kendall, C., Mundy, P., Rainey, H., Goodwin, W., Mhlanga, W. & Murn, C.
BirdLife International (2021) Species factsheet: Trigonoceps occipitalis. Downloaded from http://www.birdlife.org on 23/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/01/2021.