White-Backed Vulture (Gyps africanus)
Vultures around the world face the threat of becoming extinct in our lifetime. Vultures provide an invaluable ‘clean-up’ service to the ecosystem. Without them disease would be rife and a boom in other scavengers would occur. These scavengers do not possess the unique digestive ability that vulture do – the mechanism that prevents the spread of disease and assists in the efficient decomposition of carrion.
In the next few articles, we will focus on three vulture species found in Southern Africa, all of which face the threat of extinction and are the focus of Wildlife ACT’s vulture projects. The species include, the White-backed vulture, the White-headed vulture and the Lappet-faced vulture.
White-Backed Vulture: What Do They Look Like?
The White-backed vulture is medium in size (94cm) in comparison to its counterparts and a brown to cream colour in its adult form, with juveniles darker. Dark tail feathers with a white rump patch and ruff (Birdlife International, 2016). Their bills have a pale outer half and show little contrast between underwing-coverts and flight feathers when viewed from below – identifying features often confused with Rüppells vulture, Gyps rueppellii and Griffon vulture, Gyps fulvus – species which occupy the same range (Birdlife International, 2016).
Where Do We Find Them?
White-backed vultures are found in open wooded savanna and scattered trees, such as areas populated by Acacia (Birdlife International, 2016) and Mopane trees (Colosphermum mopane) (Biodiversity Explorer, ND). They are mainly a lowland species but do however require tall trees for nesting and are often found nesting on electricity pylons in South Africa (Birdlife International, 2016). They nest in loose colonies (Birldlife International, 2016).
White-backed vultures occupy most of the African continent and were once one of the most widespread and common vulture species (Birdlife International, 2016). In recent years, however, they have begun to rapidly decline – disappearing altogether from some of their range.
Northern Cameroon has seen White-backed vultures disappear altogether from the region. The Masai Mara has witnessed a 52% decline in numbers over the last 15 years, and little or no sightings in Yankari Game Reserve, Nigeria (one of the strongholds) and population numbers have also declined in Sudan and South Sudan (Birdlife International, 2016).
Population numbers in Ethiopia, Tanzania and Uganda appear to be more stable – with short term increases occurring (Birdlife International, 2016). Across southern Africa it is estimated that 40,000 individuals remain (Birdlife International, 2016). Studies conducted in Kimberley, South Africa, have shown an increase in breeding pairs by 72% in 22 years (Birdlife International, 2016), from 50 to 86 breeding pairs.
This may present good news in the short term; however the threats they face should not be ignored. By 2034, exploitation may lead to numbers declining to the point of local extinctions (Birdlife International, 2016).
White-Backed Vulture Distribution
Juvenile and immature birds generally migrate up to 1500 km’s from their parents territories (Biodiversity Explorer, ND).
White-Backed Vulture (Gyps africanus): Breeding
White-backed vultures are primarily monogamous and generally found nesting singly or in loose colonies (Biodiversity Explorer, ND). Loose colonies often have up to 10 breeding pairs 50-200 meters apart in scattered trees (Biodiversity Explorer, ND). Nests are made up of a platform of sticks lined with dry grass and the occasional cluster of green leaves (Biodiversity Explorer, ND). Nests can be found on tree tops or on top of man-made structures, ranging from 7-25 meters in height, with the following sites being favoured (Biodiversity Explorer, ND):
- Nigrescens (Knob thorn)
- Galpinii (Monkey acacia)
- Erioloba (Camel thorn)
- Tortillis (Umbrella thorn)
- Xanthophloea (Fever-tree acacia)
- Ficus sycomorus (Sycomore fig)
- Euclea pseudebenus (Black ebony)
- Adansonia digitata (Baobab)
- Philanoptera violacea (Apple-leaf)
- Hyphaene coriacea (Lala-palm)
- Power pylon
- On top of an old nest of another bird, such as:
– Polemaetus bellicosus (Martial eagle)
– Aquila spilogaster (African hawk-eagle)
– Sagittarius serpentarius (Secretary bird)
– Bubalornis niger (Redbilled Buffalo Weaver)
Breeding season differs between the various regions – April to July in southern parts of Africa and June to September in KwaZulu-Natal (Biodiversity Explorer, ND). One egg is laid and both parents care for it for 58 days (Biodiversity Explorer, ND). Once hatched, the parents take shifts (usually 1-2 changes per day) to care for the chick (Biodiversity Explorer, ND). The chick receives food from both parents and begins to leave the nest between 108-140 days after hatching. The vulture chick is fully independent around 5-6 months later (Biodiversity Explorer, ND).
Laying one egg per breeding season (and only having one breeding season per year), poses an even greater threat to the White-backed vulture’s existence should one or both parents no longer be around to care for the chick, or if the chick dies. Unlike other species that produce a large number of offspring to increase the chances of survival, vultures have a much tougher challenge of ensuring the one-and-only offspring produced makes it to breeding age.
What Do White-baked Vultures Eat?
Like all vultures, the White-backed is a scavenger feeding on prey left behind by other animals or feeding on the carcasses of dead animals that have succumbed to disease, wounds, or old age. Its diet mainly consists of carrion which it searches for from the air – often relying on other scavenger birds or mammalian carnivores to lead it to a carcass (Biodiversity Explorer, ND).
They are aggressive feeders – often pushing other animals away from a carcass (Biodiversity Explorer, ND). Outstretched necks and wings help White-backed vultures display a threatening stance to scare off other animals – allowing it to get to its meal (Biodiversity Explorer, ND). It is however not aggressive to larger vulture species – often becoming subordinate to the point of becoming stuck inside a carcass and subsequently eaten by other scavengers! (Biodiversity Explorer, ND).
Primarily a scavenger, White-backed vultures will however hunt if the need arises – preying on young Springbok (Antidorcas marsupialis), Red-billed quelea chicks and Warthogs (Phacochoerus aethiopicus) (Biodiversity Explorer, ND).
What Threats Do White-backed Vultures Face?
Leading to a decline in wild ungulate numbers and thus reducing the amount of carrion in the environment for vultures to feed on.
POACHED FOR MEAT AND BODY PARTS
Hunted for the bush-meat and the traditional medicine trade: poisoned directly and indirectly. Direct poisoning is a result of the poaching industry. Poachers see vultures as an alarm bell for anti-poaching forces. Therefore vultures are poisoned so as not to raise the alarm – allowing poachers to hunt down the animals they require for the black market (Birdlife International, 2016). Vultures often succumb to indirect or accidental poisoning when they ingest poisoned carrion – often from the pesticide carbofuran (Birdlife International, 2016).
In parts of the world, namely South East Asia and parts of Africa (Tanzania), the veterinary anti-inflammatory (diclofenac) drug is often administered to livestock; a drug that if ingested by vultures is fatal (Birdlife International, 2016). In 2007, the drug was aggressively pushed into the veterinary industry by a Brazilian manufacturer and ended up being exported to 15 African countries (Birdlife International, 2016). Thankfully, in many regions of Africa, livestock carrion is generally not left out for scavengers (unlike in parts of South East Asia) and thus does not pose as great a threat (Birdlife International, 2016).
Southern African vulture populations face the threat of being killed for use in the traditional medicine industry (muthi trade), and are believed to provide psychological benefits (Birdlife International, 2016). In other regions of Africa such as Nigeria, vultures are hunted and parts traded for use in traditional juju practices (Birdlife International, 2016). Studies conducted in 2007 by McKean and Botha suggests that the continued use of vulture parts in the traditional medicine trade as well as environmental threats, will cause the species to become locally extinct within 26 years (Birdlife International, 2016).
Further to all the aforementioned threats, many vultures succumb to electrocution by power-lines within their flight paths and range (Birdlife International, 2016) therefore impacting their numbers even further.
Current global population data suggests that there are as few as 270, 000 individuals left in the wild, with declines of around 75 to 95% in many parts of its range (Birdlife International, 2016). Numbers differ between various regions within its range and the common trend is that they are declining in all parts of it…
For more information about population numbers, life cycles, breeding success rates and more, below are a few links for further reading:
- Birdlife International
- IUCN Red list of threatened species
- Global Raptor Information Network. 2017. Species account: White-backed Vulture Gyps africanus
Birdlife International. (2016). Gyps africanus. The IUCN Red List of Threatened Species 2016: Accessed online 25/02/2017
Article composed by Rhiannon Gill