White-backed vulture

Last updated

White-backed vulture
2012-white-backed-vulture.jpg
At Etosha National Park
White-backed Vulture (Gyps africanus) (31053364872).jpg
At Lower Sabie, Kruger National Park
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Gyps
Species:
G. africanus
Binomial name
Gyps africanus
Salvadori, 1865
White-backed vulture
  Extant (resident)
  Extant (non-breeding)
  Possibly extant (resident)
  Possibly extinct
  Extinct

The white-backed vulture (Gyps africanus) is an Old World vulture in the family Accipitridae, which also includes eagles, kites, buzzards and hawks. It is the most common vulture species in the continent of Africa. [2]

Contents

Description

Preening at the Kgalagadi Transfrontier Park White-backed Vulture, Gyps africanus, at Kgalagadi Transfrontier Park, Northern Cape, South Africa. (46112754012).jpg
Preening at the Kgalagadi Transfrontier Park

The white-backed vulture is a typical vulture, with only down feathers on the head and neck, very broad wings and short tail feathers. It has a white neck ruff. The adult's whitish back contrasts with the otherwise dark plumage. Juveniles are largely dark. This is a medium-sized vulture; its body mass is 4.2 to 7.2 kg (9.3–15.9 lb), it is 78 to 98 cm (31 to 39 in) long and has a 1.96 to 2.25 m (6 ft 5 in to 7 ft 5 in) wingspan. [3] [4] [5]

Distribution and habitat

The white-backed vulture occurs from Senegal, Gambia and Mali in the west, throughout the Sahel region to Ethiopia and Somalia in the east, through East Africa into Mozambique, Zimbabwe, Botswana, Namibia and South Africa in the south. [1] It is the most widespread and common vulture in Africa with an estimated range of 24,300,000 km2 (9,400,000 sq mi), but has undergone rapid population declines in recent years. [1]

Conservation

The white-backed vulture, like many African vultures, has suffered a rapid decline. When it was first assessed in 1988 it was classified as a Least concern species owing to a large range and population. It was reassessed from a Least Concern to Near Threatened species in the 2007 IUCN Red List after the beginnings of a major decline were noticed. [6] In 2012, more information was available about population trends, and the estimates suggested that within the next three generations the white-backed vulture would decrease by 50%. Consequently it was added to the list of Endangered species. [7] In October 2015, it was further uplisted to Critically Endangered because the decline had reach a magnitude that puts the vulture at an extreme risk of extinction. [1]

The population size of the white-backed vulture has been decreasing significantly within the past few decades. In 1992, the population was estimated at 270,000. Over the past two decades, its population has noticeably decreased. BirdLife international estimated that over the past 40 years, the population of the white-backed vulture has decreased annually by a mean of 4.1%, culminating to an overall decline that lies between 63 and 89%, and such harrowing declines have also been recorded in the populations of its other African relatives. [1] A recent study found that white-backed vultures have a high survival rate. Individual adults have the highest survival rate, while 2 year old birds have the lowest survival rate. Across all ages, the survival rate is estimated to be 90.7%. This means that the deaths of adult vultures will lead to rapid population declines. The loss of adults will cause less reproduction and with younger birds less likely to survive, the population will drop drastically. A major cause of population decrease is the loss of habitat and anthropogenic disturbance. Fires have also caused the destruction of trees used for nesting habitat. Humans also have a large impact. Power lines have caused many vultures to be electrocuted. In Kenya especially, humans are using a toxic pesticide called Furadan, which has led to many vulture deaths. Vultures are also being poisoned by humans, although not intentionally. In order to kill hyenas, lions, and other predators, herders add poisons into their livestock. Vultures ingest the poison upon eating a deceased animal's carcass. This poisoning generally occurs outside of protected areas but is a leading factor in the population's decline. Habitats are also being disturbed by human land management and direct nesting persecution patterns.

More recent studies have indicated a new plausible factor in the current declination of the vultures. Researches have seen that there has been a rise in toxicity in the liver, kidneys, pectoral region, and internal organs. This toxicity is caused by higher levels of lead, cadmium, zinc, and copper. Although most of these metals level out as either non harmful or normal levels, the lead concentrate in the liver of the vultures (8.56 μg/g wet weight) and in the kidneys (9.31 μg/g wet weight) is higher than the average levels.

Studies have also been performed on the white-backed vulture and some species of Asian vultures within the Gyps clade to see the effect of veterinary diclofenac. [8] Regardless of whether the vultures were given an oral or intravenous dose of the substance, the effects was nearly identical and the diclofenac eventually poisoned the subjects. [9] This chemical is one of the greatest contaminants for the general vulture population because of its presence in livestock: easy food for the vultures.

Another study shows that there are heightened levels of polycyclic aromatic hydrocarbons (HPA's), which is not as likely a product in the endangerment resultant, but still concerning. HPA's, also known as polyaromatic hydrocarbons, are formations of hydrogen atoms surrounding rings of carbon. As common as these compounds are—found in foods, engines/incinerators, fires, combustion—there are many forms, and some carcinogenic. Although there is no direct correlation of the high levels of HPA's in the vultures, there is still a plausibility that it can result in a negative outcome for the species.

Another reason for the decline in the number of white-backed vultures is the decrease in the number of their nesting sites, which they construct in trees in savannah areas and which are roughly 1 meter in diameter. There is an inverse relationship between the amount of human activity (farming, ranching, etc.) and the amount of vulture nesting activity in said area, so as the amount of human activity in Africa expands, the number of nesting sites available decreases, putting the vultures at jeopardy. [10]

On the 20th of June 2019, the corpses of 468 white-backed vultures, 17 white-headed vultures, 28 hooded vultures, 14 lappet-faced vultures and 10 cape vultures, altogether 537 vultures, besides 2 tawny eagles, were found in northern Botswana. It is suspected that they died after eating the corpses of 3 elephants that were poisoned by poachers, possibly to avoid detection by the birds, which help rangers to track poaching activity by circling above where there are dead animals. Most of them were new parents, leaving their young orphaned and "ill-equipped" for survival. Vultures are slow breeders, and losing over 400 on a week is a devastating blow for the species. [11] [12] [13] [14]

Diet and feeding behaviour

Group feeding on a zebra carcass, Upper Lupande GMA, Zambia Vultures Zebra Skeleton Luangwa Zambia Jul23 A7C 06076.jpg
Group feeding on a zebra carcass, Upper Lupande GMA, Zambia

White-backed vultures are obligate scavengers with a high level of specialization on carrion. Their primary food sources are the carcasses of large, grazing animals found the wooded savannahs where it lives. This includes warthogs, zebras, gazelles, ostriches and even livestock. Their beaks are medium-sized not adapted for tearing through tough skin, so they are limited to eating soft tissues, such as the viscera, using a pulling feeding tactic. [15]

White-backed vultures circle through the sky in search of freshly dead animals, often following other scavenger birds and mammalian carnivores to find it. [16] Gyps vultures are considered social vultures which rely heavily on conspecifics to provide information about the position of food and carcasses. [17] Once a carcass is found, they will begin wheeling in the sky, signalling their discovery to other vultures.[ citation needed ] White-backed vultures feed in groups and are often one of the first vulture species to arrive at a carcass. [18] This leads to this species having a high dominance at carcasses in comparison to other vulture species such as white-headed, hooded, and Egyptian vultures.

After feeding, white-backed vultures often rest with their wings spread and their backs facing the sun, as they have gorged themselves so much they can no longer fly.[ citation needed ]

Breeding

White-backed Vulture eggs in nest in Atherstone Nature Reserve 1.jpg
White-backed Vulture eggs in a nest in Atherstone Nature Reserve
Vautour africain MHNT.jpg
Egg

White-backed vultures nest in trees. They typically choose tall trees along riparian habitats and show strong a preference for Acacia species. The nests are large, around 1m in diameter, and are made of large sticks and lined with leaves and grasses.

A study which monitored 32 African white-backed vulture nests in the Masai Mara National Reserve during the period 2003 to 2007 showed that the mean nesting success was 59%. [19] Another long-term study conducted in Linyanti, Botswana found that there were rapid declines in nesting numbers during a 10 year period. [20] In 2007, there were 73 breeding pairs nesting in the area with a minimum density of 14.9 nests per 100 square kilometers. By 2017, this declined to 22 breeding pairs nesting and 4.49 nests per 100 square kilometers. In addition to a decrease in the number of active nests in the area, breeding success declined from 62% in 2006 to 37% in 2017.

White-backed vultures face threats from habitat degradation and poaching; as such they have been shown to avoid anthropogenically-disturbed areas when selecting nest sites and protection status is also a strong determinant of site selection. [21]

White-backed vultures have a long breeding cycle. The incubation period is around 8 weeks and the nestling period is about 4–5 months. [22]

Ecology

The tick Argas theilerae (also known as Theiler's African White-backed vulture argasid) is a parasite of the White-backed vulture. [23]

See also

Footnotes

  1. 1 2 3 4 5 BirdLife International (2021). "Gyps africanus". IUCN Red List of Threatened Species . 2021: e.T22695189A204461164. doi: 10.2305/IUCN.UK.2021-3.RLTS.T22695189A204461164.en . Retrieved 2022-05-30.
  2. "white-backed vulture". african geographic. Retrieved 20 September 2022.
  3. "White-backed vulture videos, photos and facts - Gyps africanus". ARKive. Archived from the original on 2012-05-29. Retrieved 2011-05-31.
  4. Raptors of the World by Ferguson-Lees, Christie, Franklin, Mead & Burton. Houghton Mifflin (2001), ISBN   0-618-12762-3
  5. "African White-backed Vulture". Oiseaux-birds. Retrieved 2011-10-11.
  6. See BirdLife International (2007a. b).
  7. "Recently recategorised species". Birdlife International (2012). Retrieved 15 June 2012.
  8. Bamford, et.al. Trade-offs between specificity and regional generality in habitat association models: a case study of two species of African vulture. Journal of Applied Ecology, 46: 853-859.
  9. Naidoo V, Wolter K, Cuthbert R, Duncan N. 2009. Veterinary diclofenac threatens Africa's endangered vulture species. Regul Toxicol Pharmacol 53:205–208.
  10. BAMFORD, A. J., MONADJEM, A., & HARDY, I. C. (2008, September 16). Nesting habitat preference of the African White‐backed Vulture Gyps africanus and the effects of anthropogenic disturbance. Retrieved February 23, 2018, from http://onlinelibrary.wiley.com/doi/10.1111/j.1474-919X.2008.00878.x/full
  11. "Over 500 Rare Vultures Die After Eating Poisoned Elephants In Botswana". Agence France-Press . NDTV. 2019-06-21. Retrieved 2019-06-28.
  12. Hurworth, Ella (2019-06-24). "More than 500 endangered vultures die after eating poisoned elephant carcasses". CNN . Retrieved 2019-06-28.
  13. Solly, Meilan (2019-06-24). "Poachers' Poison Kills 530 Endangered Vultures in Botswana". Smithsonian . Retrieved 2019-06-28.
  14. Ngounou, Boris (2019-06-27). "BOTSWANA: Over 500 vultures found dead after massive poisoning". Afrik21. Retrieved 2019-06-28.
  15. Mundy, P; Butchart, D; Ledger, J; Piper, S (1992). The Vultures of Africa. Randburg, South Africa: Acorn Books.
  16. Gill, Rhiannon. "White-Backed Vulture (Gyps africanus)". wildlifeact.com. Wildlife Act. Retrieved 30 July 2020.
  17. Jackson, Andrew L; Ruxton, Graeme D; Houston, David C (2008). "The effect of social facilitation on foraging success in vultures: a modelling study". Biology Letters. 4 (3): 311–313. doi:10.1098/rsbl.2008.0038. ISSN   1744-9561. PMC   2610049 . PMID   18364309.
  18. Kendall, C; Virani, M; Kirui, P; Thomsett, S; Githiru, M (2012). "Mechanisms of Coexistence in Vultures: Understanding the Patterns of Vulture Abundance at Carcasses in Masai Mara National Reserve, Kenya". The Condor. 114 (3): 523–531. doi: 10.1525/cond.2012.100196 . ISSN   1938-5129. S2CID   55624422.
  19. Virani, M (2010). "Nesting status of African White-backed Vultures Gyps Africanus in the Masai Mara National Reserve, Kenya". Ostrich. 81 (3): 205–209. doi:10.2989/00306525.2010.519894. S2CID   86549912.
  20. Leepile, Leungo B. L.; Maude, Glyn; Hancock, Pete; Reading, Richard P.; Bridges, Brian; Hartley, Robyn; Amar, Arjun (2020). "Changes in nesting numbers and breeding success of African White-backed Vulture Gyps africanus in north-central Botswana". Bird Conservation International. 30 (3): 456–473. doi:10.1017/S0959270920000179. ISSN   0959-2709. S2CID   219001377.
  21. Bamford, Andrew J.; Monadjem, Ara; Hardy, Ian C. W. (2009). "Nesting habitat preference of African White-backed Vulture Gyps africanus and the effect of anthropogenic disturbance". Ibis (151): 51–62. doi:10.1111/j.1474-919X.2008.00878.x.
  22. Kemp, A. C.; Kemp, M. I. (1975). "Observations on the White backed Vulture Gyps africanus in the Kruger National Park, with notes on other avian scavengers". Koedoe (18): 51–68.
  23. Hoogstraal, Harry; Kaiser, Makram N. (1970-01-15). "The Subgenus Persicargas (Ixodoidea, Argasidae, Argas). 8. A. (P.) theilerae, New Species, a Parasite of the White-Backed Vulture in South Africa". Annals of the Entomological Society of America. 63 (1): 205–210. doi:10.1093/aesa/63.1.205. ISSN   1938-2901.

Related Research Articles

<span class="mw-page-title-main">Vulture</span> Common name for a type of bird

A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture. Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and South America and consist of seven identified species, all belonging to the Cathartidae family. A particular characteristic of many vultures is a bald, unfeathered head. This bare skin is thought to keep the head clean when feeding, and also plays an important role in thermoregulation.

<span class="mw-page-title-main">Old World vulture</span> Informal group of birds

Old World vultures are vultures that are found in the Old World, i.e. the continents of Europe, Asia and Africa, and which belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.

<span class="mw-page-title-main">Eurasian griffon vulture</span> Species of bird

The Eurasian griffon vulture is a large Old World vulture in the bird of prey family Accipitridae. It is also known as the Griffon vulture, although this term is sometimes used for the genus as a whole. It is not to be confused with the Rüppell's griffon vulture and Himalayan griffon vulture. It is closely related to the white-backed vulture.

<span class="mw-page-title-main">Himalayan vulture</span> Species of bird

The Himalayan vulture or Himalayan griffon vulture is an Old World vulture native to the Himalayas and the adjoining Tibetan Plateau. It is one of the two largest Old World vultures and true raptors. It is listed as Near Threatened on the IUCN Red List. It is not to be confused with the Eurasian griffon vulture, which is a similar and sympatric species.

<span class="mw-page-title-main">White-rumped vulture</span> Species of bird

The white-rumped vulture is an Old World vulture native to South and Southeast Asia. It has been listed as Critically Endangered on the IUCN Red List since 2000, as the population severely declined. White-rumped vultures die of kidney failure caused by diclofenac poisoning. In the 1980s, the global population was estimated at several million individuals, and it was thought to be "the most abundant large bird of prey in the world". As of 2021, the global population was estimated at less than 6,000 mature individuals.

<span class="mw-page-title-main">Indian vulture</span> Species of vulture

The Indian vulture or long-billed vulture is a bird of prey native to the Indian subcontinent. It is an Old World vulture belonging to the family of Accipitridae. It is a medium-sized vulture with a small, semi-bald head with little feathers, long beak, and wide dark colored wings. It breeds mainly on small cliffs and hilly crags in central India and south India.

<span class="mw-page-title-main">Hooded vulture</span> Species of bird

The hooded vulture is an Old World vulture in the order Accipitriformes, which also includes eagles, kites, buzzards and hawks. It is the only member of the genus Necrosyrtes, which is sister to the larger Gyps genus, both of which are a part of the Aegypiinae subfamily of Old World vultures. It is native to sub-Saharan Africa, where it has a widespread distribution with populations in southern, East and West Africa. It is a scruffy-looking, small vulture with dark brown plumage, a long thin bill, bare crown, face and fore-neck, and a downy nape and hind-neck. Its face is usually a light red colour. It typically scavenges on carcasses of wildlife and domestic animals. Although it remains a common species with a stable population in the lower region of Casamance, some areas of The Gambia, and Guinea-Bissau, other regions such as Dakar, Senegal, show more than 85% losses in population over the last 50 years. Threats include poisoning, hunting, loss of habitat and collisions with electricity infrastructure, and the International Union for Conservation of Nature has rated its conservation status as "critically endangered" in their latest assessment (2022). The highest current regional density of hooded vultures is in the western region of The Gambia.

<span class="mw-page-title-main">Lappet-faced vulture</span> Species of bird

The lappet-faced vulture or Nubian vulture is an Old World vulture belonging to the bird order Accipitriformes, which also includes eagles, kites, buzzards and hawks. It is the only member of the genus Torgos. It is not closely related to the superficially similar New World vultures, and does not share the good sense of smell of some members of that family of birds.

<span class="mw-page-title-main">Cinereous vulture</span> Species of bird

The cinereous vulture is a large raptor in the family Accipitridae and distributed through much of temperate Eurasia. It is also known as the black vulture, monk vulture and Eurasian black vulture. With a body length of 1.2 m, 3.1 m (10 ft) across the wings and a maximum weight of 14 kg (31 lb), it is the largest Old World vulture and largest member of the Accipitridae family.

<span class="mw-page-title-main">Rüppell's vulture</span> Species of bird

Rüppell's vulture, also called Rüppell's griffon vulture, named after Eduard Rüppell, is a large bird of prey, mainly native to the Sahel region and East Africa. The former population of 22,000 has been decreasing due to loss of habitat, incidental poisoning, and other factors. Known also as Rüppell's griffon, Rueppell's griffon, Rüppell's griffin vulture, Rueppell's vulture and other variants, it is not to be confused with a different species, the griffon vulture. Rüppell's vulture is considered to be the highest-flying bird, with confirmed evidence of a flight at an altitude of 11,300 m (37,000 ft) above sea level.

<span class="mw-page-title-main">Tawny eagle</span> Species of bird

The tawny eagle is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. Its heavily feathered legs mark it as a member of the subfamily Aquilinae, also known as booted eagles. Tawny eagles have an extensive but discontinuous breeding range that constitutes much of the African continent as well as the Indian subcontinent, with rare residency in the southern Middle East. Throughout its range, it favours open dry habitats such as semideserts, deserts steppes, or savanna plains. Despite its preference for arid areas, the species seldom occurs in areas where trees are entirely absent. It is a resident breeder which lays one to three eggs in a stick nest most commonly in the crown of a tree. The tawny eagle is perhaps the most highly opportunistic of all Aquilinae, and often scavenges on carrion or engages in kleptoparasitism towards other carnivorous animals but is also a bold and active predator, often of relatively large and diverse prey. It is estimated that tawny eagles can reach the age of 16 years old. Nonetheless, precipitous declines have been detected throughout the tawny eagle's range. Numerous factors, particularly loss of nesting habitat due to logging and global warming, as well as persecution and other anthropogenic mortality are driving the once numerous tawny eagle perhaps to the brink of extinction.

<span class="mw-page-title-main">Cape vulture</span> Species of bird

The Cape vulture, also known as Cape griffon and Kolbe's vulture, is an Old World vulture in the family Accipitridae. It is endemic to southern Africa, and lives mainly in South Africa, Lesotho, Botswana, and in some parts of northern Namibia. It nests on cliffs and lays one egg per year. In 2015, it had been classified as Endangered on the IUCN Red List, but was down-listed to Vulnerable in 2021 as some populations increased and have been stable since about 2016.

<span class="mw-page-title-main">Slender-billed vulture</span> Species of bird

The slender-billed vulture is an Old World vulture species native to sub-Himalayan regions and Southeast Asia. It is Critically Endangered since 2002 as the population on the Indian subcontinent has declined rapidly. As of 2021, fewer than 870 mature individuals are thought to remain.

<span class="mw-page-title-main">Red-headed vulture</span> Species of bird

The red-headed vulture, also known as the Asian king vulture, Indian black vulture or Pondicherry vulture, is an Old World vulture mainly found in the Indian subcontinent, with small disjunct populations in some parts of Southeast Asia.

<span class="mw-page-title-main">Bateleur</span> Species of bird

The bateleur is a medium-sized eagle in the family Accipitridae. It is often considered a relative of the snake eagles and, like them, it is classified within the subfamily Circaetinae. It is the only member of the genus Terathopius and may be the origin of the "Zimbabwe Bird", the national emblem of Zimbabwe. Adult bateleurs are generally black in colour with a chestnut colour on the mantle as well as also on the rump and tail. Adults also have gray patches about the leading edges of the wings with bright red on their cere and their feet. Adults also show white greater coverts, contrasting with black remiges in males, gray patches on the underwing primaries and black wingtips. The juvenile bateleur is quite different, being largely drab brown with a bit of paler feather scaling. All bateleurs have extremely large heads for their size, rather small bills, large feet, relatively short legs, long, bow-like wings and uniquely short tails, which are much smaller still on adults compared to juvenile birds.

<span class="mw-page-title-main">White-headed vulture</span> Species of bird

The white-headed vulture is an Old World vulture endemic to Africa. Populations have been declining steeply in recent years due to habitat degradation and poisoning of vultures at carcasses. An extinct relative was also present in the Indonesian island of Flores during the Late Pleistocene, indicating that the genus was more widespread in the past.

<span class="mw-page-title-main">Indian vulture crisis</span> Ecological crisis in Indian subcontinent

Nine species of vulture can be found living in India, but most are now in danger of extinction after a rapid and major population collapse in recent decades. In the early 1980s, three species of Gyps vultures had a combined estimated population of 40 million in South Asia, while in 2017 the total population numbered only 19,000.

<span class="mw-page-title-main">Jatayu Conservation Breeding Centre, Pinjore</span> Critically Endangered Bird Breeding Centre in Haryana, India

The Jatayu and Sparrow Conservation Breeding Centre (JCBC), is the world's largest facility for the breeding and conservation of Indian vultures and the house sparrow. It is located within the Bir Shikargah Wildlife Sanctuary in the town of Pinjore in the State of Haryana, India. It is run by the Haryana Forests Department and Bombay Natural History Society with the help of British nature conservation charity Royal Society for the Protection of Birds. It is 8 kilometres (5.0 mi) from Pinjore and covers 5 acres (2.0 ha).

A vulture restaurant is a site where carrion, decaying flesh from dead animals, is deposited in order to be consumed by vultures, and is sometimes referred to more generally as supplemental feeding or provisioning. These stations can also be referred to as vulture feeding sites, vulture feeding stations, and vulture safe zones. This supplemental feeding practice is used to provide vultures with reliable, non-contaminated food sources or to aid in monitoring schemes. Vulture restaurants have been instituted as a method of vulture conservation in Europe and Africa since the 1960's and 70's, when vulture populations began to decline. This strategy is used because often population declines are attributed to low food availability, food contamination or insufficient nutritional quality, or feeding from human areas leading to conflict. Notably, large vulture population declines in South Asia, referred to as the Asian or Indian vulture crisis, and Africa, referred to as the African vulture crisis, have brought renewed attention to the uses and impacts of vulture restaurants. Vulture restaurants are used in Asia, Africa, Europe, and North America for various conservation and management plans. They can help combat food-derived threats to vultures, such as diclofenac or lead contamination or conflict with ranchers and poachers. The first vulture restaurant was built in South Africa in 1966. Vulture restaurants operate in a number of countries, including Nepal, India, Cambodia, South Africa, Eswatini, and Spain.

<span class="mw-page-title-main">African vulture crisis</span> Ecological disaster in Africa

The African vulture crisis is the name given to the ongoing population decline in several Old World vulture species across Africa. Steep population declines have been reported from many locations across the continent since the early 2000s. The causes are mainly poisoning from baited animal carcasses, and the illegal trade in vulture body parts for traditional medicine. Available data suggest that the African vulture crisis may be similar in scale to the Indian vulture crisis, but more protracted and less well documented.

References