Vulture

Summary

Vulture
Temporal range: Miocene – Recent
[1]
Bartgeier Gypaetus barbatus front Richard Bartz.jpg
Lammergeier at Alpenzoo, Innsbruck, Austria
Coragyps-atratus-001.jpg
Black vulture in Panama
Scientific classification
Kingdom:
Phylum:
Class:
Families

A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture (including Condors).[2] 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[2][3] 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.[4]

Vultures have been observed to hunch their bodies and tuck in their heads in the cold, and open their wings and stretch their necks in the heat. They also urinate on themselves as a means of cooling their bodies.[5]

A group of vultures in flight is called a 'kettle', while the term 'committee' refers to a group of vultures resting on the ground or in trees. A group of vultures that are feeding is termed 'wake'.[6]

Taxonomy

Although New World vultures and Old World vultures share many resemblances, they are not very closely related. Rather, they share resemblance because of convergent evolution.[7]

Early naturalists placed all vultures under one single biological group. Carl Linnaeus had assigned both Old World vultures and New World vultures in a Vultur genus, even including the Harpy eagle. Soon anatomists split Old and New World vultures, with New World vultures being placed in a new suborder, Cathartae, later renamed Cathartidae as per the Rules of Nomenclature (from Greek: carthartes, meaning "purifier")[8] by French ornithologist Frédéric de Lafresnaye.[9] The suborder was later recognised as a family, rather than a suborder.

In the late 20th century some ornithologists argued that New World vultures are more closely related to storks on the basis of karyotype,[10] morphological,[11] and behavioral[12] data. Thus some authorities placed them in the Ciconiiformes family with storks and herons; Sibley and Monroe (1990) even considered them a subfamily of the storks. This was criticized,[13][14] and an early DNA sequence study[15] was based on erroneous data and subsequently retracted.[16][17][18] There was then an attempt to raise the New World vultures to the rank of an independent order, Cathartiformes not closely associated with either the birds of prey or the storks and herons.[19]

Old World vultures

Some members of both the Old and New World vultures have an unfeathered neck and head, shown as radiating heat in this thermographic image
Griffon vultures scavenging a red deer carcass in Spain
Griffon vulture soaring
Vulture preparing to land in Kenya
African hooded vulture in Kruger National Park
A wake of white-backed vultures eating a wildebeest carcass at Maasai Mara
Nekhbet with staff and shen ring
Flock of white-rumped vultures in India
Head of a vulture chick at Mellat Park, Tehran City, Iran

The Old World vultures found in Africa, Asia, and Europe belong to the family Accipitridae, which also includes eagles, kites, buzzards, and hawks. Old World vultures find carcasses exclusively by sight.

The 16 species in 9 genera are:

New World vultures

(Coragyps atratus) American black vulture wake at road kill
American Black Vulture congregated at roadkill site

The New World vultures and condors found in warm and temperate areas of the Americas are not closely related to the similar Accipitridae, but belong in the family Cathartidae, which was once considered to be related to the storks. However, recent DNA evidence suggests that they should be included among the Accipitriformes, along with other birds of prey. However, they are still not closely related to the other vultures. Several species have a good sense of smell, unusual for raptors, and are able to smell dead animals from great heights, up to a mile away.

The seven species are:

Feeding

Vultures are scavengers, meaning they eat dead animals. Outside of the oceans, vultures are the only known obligate scavengers.[20] They rarely attack healthy animals, but may kill the wounded or sick. When a carcass has too thick a hide for its beak to open, it waits for a larger scavenger to eat first.[21] Vast numbers have been seen upon battlefields. They gorge themselves when prey is abundant, until their crops bulge, and sit, sleepy or half torpid, to digest their food. These birds do not carry food to their young in their talons but disgorge it from their crops. The mountain-dwelling bearded vulture is the only vertebrate to specialize in eating bones,[22] and does carry bones to the nest for the young, and it hunts some live prey.

Vultures are of great value as scavengers, especially in hot regions. Vulture stomach acid is exceptionally corrosive (pH=1.0[22]), allowing them to safely digest putrid carcasses infected with botulinum toxin, hog cholera bacteria, and anthrax bacteria that would be lethal to other scavengers[23] and remove these bacteria from the environment. New World vultures often vomit when threatened or approached. Contrary to some accounts, they do not "projectile vomit" on their attacker in defence, but to lighten their stomach load to ease take-off. The vomited meal residue may distract a predator, allowing the bird to escape.[24]

New World vultures also urinate straight down their legs; the uric acid kills bacteria accumulated from walking through carcasses, and also acts as evaporative cooling.[25]

Conservation status

Vultures in south Asia, mainly in India and Nepal, have declined dramatically since the early 1990s.[26] It has been found that this decline was caused by residues of the veterinary drug Diclofenac in animal carcasses.[27] The government of India has taken very late cognizance of this fact and has banned the drug for animals.[28] However, it may take decades for vultures to come back to their earlier population level, if they ever do: without vultures to pick corpses clean, rabies-carrying dogs have multiplied, feeding on the carrion, and age-old practices like the sky burials of the Parsees are coming to an end, permanently reducing the supply of corpses.[29] The same problem is also seen in Nepal where government has taken some late steps to conserve remaining vultures. Similarly, in Central Africa there has also been efforts to conserve the remaining vultures and bring their population numbers back up. This is largely due to the bushmeat trade, "it is estimated > 1 billion kg [2.2 billion lb] of wild animal meat is traded" and vultures take up a large percentage of this bushmeat due to their demand in the fetish market.[30] The substantial drop in vulture populations in the continent of Africa is also said to be the result of both intentional and unintentional poisoning, with one study finding it to be the cause of 61% of the vulture deaths recorded.[31]

The vulture population is threatened across Africa and Eurasia. There are many anthropogenic activities that threaten vultures such as poisoning and wind energy collision mortality.[32]

A recent study in 2016, reported that "of the 22 vulture species, nine are critically endangered, three are endangered, four are near threatened, and six are least concern".[33]

The conservation status of vultures is of particular concern to humans. For example, the decline of vulture populations can lead to increased disease transmission and resource damage, through increased populations of disease vector and pest animal populations that scavenge carcasses opportunistically. Vultures control these pests and disease vectors indirectly through competition for carcasses.[34]

On 20 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.[35][36][37][38]

In myth and culture

In Ancient Egyptian art, Nekhbet, a mythological goddess and patron of both the city of Nekheb and Upper Egypt[39] was depicted as a vulture. Alan Gardiner identified the species that was used in divine iconography as a griffon vulture. Arielle P. Kozloff, however, argues that the vultures in New Kingdom art, with their blue-tipped beaks and loose skin, better resemble the lappet-faced vulture. Many Great Royal Wives wore vulture crowns - a symbol of protection from the goddess Nekhbet.[40]

Ancient Egyptians believed that all vultures were female and were spontaneously born from eggs without the intervention of a male, and therefore linked the birds to purity and motherhood, but also the eternal cycle of death and rebirth for their ability to transform the “death” they feed on – i.e. carrion and waste – into life.[41]

The Aztec vulture vessel at the new Pre-Columbian Mesoamerican Pottery Gallery

In Pre-Columbian times, vultures were appreciated as extraordinary beings and they had high iconographic status. Vultures appear in many Mesoamerican myths, legends, and fables, with many separate civilizations such as the Mayan and Aztec developing a range of stories around vultures. Many Mesoamerican stories depict vultures negatively, while others contain more positive attitudes.[42]

In certain regions of China, India, Mongolia, and Bhutan, where Vajrayana Buddhist cultures are found, vultures play a significant role in sky burials.

See also

References

  1. ^ "Fossilworks:Aegypiinae". Fossilworks. Retrieved 17 December 2021.
  2. ^ a b "Dropping dead: causes and consequences of vulture population declines worldwide" (PDF). 2001.
  3. ^ Amadon, D. (1977). "Notes on the taxonomy of vultures" (PDF). The Condor. 79 (4): 413–416. doi:10.2307/1367720. JSTOR 1367720.
  4. ^ Ward, J.; McCafferty, D.J.; Houston, D.C. & Ruxton, G.D. (2008). "Why do vultures have bald heads? The role of postural adjustment and bare skin areas in thermoregulation". Journal of Thermal Biology. 33 (3): 168–173. doi:10.1016/j.jtherbio.2008.01.002.
  5. ^ Arad, Z. & Bernstein, M. H. (1988). "Temperature Regulation in Turkey Vultures". The Condor. 90 (4): 913–919. doi:10.2307/1368848. JSTOR 1368848.
  6. ^ Hamilton, S.L. (2014). "Sky Burials". In Galván, J. (ed.). They Do What? A Cultural Encyclopedia of Extraordinary and Exotic Customs from around the World. Santa Barbara, California: ABC-CLIO. p. 289. ISBN 978-1-61069-342-4.
  7. ^ Phillips (2000)
  8. ^ Brookes (2006)
  9. ^ Notes on the Taxonomy of Vultures The Condor Vol. 79, No. 4. 1977. pp. 413–416.
  10. ^ de Boer (1975)
  11. ^ Ligon (1967)
  12. ^ König (1982)
  13. ^ Griffiths (1994)
  14. ^ Fain & Houde (2004)
  15. ^ Avise (1994)
  16. ^ Brown (2009)
  17. ^ Cracraft et al. (2004)
  18. ^ Gibb et al. (2007)
  19. ^ Ericson et al. (2006)
  20. ^ Ruxton, G.D. & D.C. Houston. 2004. Obligate vertebrate scavengers must be large soaring fliers. J. Theor. Biol. 228: 431–436.
  21. ^ "Fast Vulture Facts". WebVulture.com. Archived from the original on July 18, 2011. Retrieved February 15, 2013.
  22. ^ a b Buechley, E. R. & Sekercioglu, C. H. (2016). "Vultures". Current Biology. 26 (13): R560–R561. doi:10.1016/j.cub.2016.01.052. PMID 27404248.
  23. ^ Caryl, Jim (September 7, 2000). "Re: How come that vultures can resist dangerous toxins when feeding on carcass". MadSci Network. Retrieved February 15, 2013.
  24. ^ "Turkey Vulture Facts". Turkey Vulture Society. Retrieved 2012-12-01.
  25. ^ Conger, Cristen (2008-10-13). "Why is it a bad idea to scare a vulture?". HowStuffWorks. Retrieved February 15, 2013.
  26. ^ Prakash, V.; Pain, D.J.; Cunningham, A.A.; Donald, P.F.; Prakash, N.; Verma, A.; Gargi, R.; Sivakumar, S. & Rahmani, A.R. =u74p \ear=2003 (2003). "Catastrophic collapse of Indian white-backedGyps bengalensis and long-billed Gyps indicus vulture populations" (PDF). Biological Conservation. 109 (3): 381–390. doi:10.1016/S0006-3207(02)00164-7.
  27. ^ Oaks, J. L.; Gilbert, Martin; Virani, M. Z.; Watson, R. T.; Meteyer, C. U.; Rideout, B. A.; Shivaprasad, H. L.; Ahmed, S.; Chaudhry, M. J. I.; Arshad, M.; Mahmood, S.; Ali, A. & Khan, A. A. (2004). "Diclofenac residues as the cause of vulture population decline in Pakistan". Nature. 427 (6975): 630–633. Bibcode:2004Natur.427..630O. doi:10.1038/nature02317. PMID 14745453. S2CID 16146840.
  28. ^ Prakash, V.; Bishwakarma, M. C.; Chaudhary, A.; Cuthbert, R.; Dave, R.; Kulkarni, M.; Kumar, S.; Paudel, K.; Ranade, S.; Shringarpure, R. & Green, R. E. (2012). "The Population Decline of Gyps Vultures in India and Nepal Has Slowed since Veterinary Use of Diclofenac was Banned". PLOS One. 7 (11): e49118. Bibcode:2012PLoSO...749118P. doi:10.1371/journal.pone.0049118. PMC 3492300. PMID 23145090.
  29. ^ van Dooren, T. (2011). "Vultures and their People in India: Equity and Entanglement in a Time of Extinctions". Australian Humanities Review (50).
  30. ^ Buij, R.; Nikolaus, G.; Ogada, D.; Whytock, R. & Ingram, D.J. (2015). "Trade of threatened vultures and other raptors for fetish and bushmeat in West and Central Africa". Fauna & Flora International. 50 (4): 606–616. doi:10.1017/S0030605315000514.
  31. ^ Ogada, D.; Shaw, P.; Beyers, R. L.; Buij, R.; Murn, C.; Thiollay, J. M.; Beale, C. M.; Holdo, R. M. & Pomeroy, D. (2016). "Another Continental Vulture Crisis: Africa's Vultures Collapsing toward Extinction". Conservation Letters. 9 (2): 89–97. doi:10.1111/conl.12182. ISSN 1755-263X.
  32. ^ Santangeli, A.; Girardello, M.; Buechley, E.; Botha, A.; Minin, E. D. & Moilanen, A. (2019). "Priority areas for conservation of Old World vultures". Conservation Biology. 33 (5): 1056–1065. doi:10.1111/cobi.13282. PMC 6849836. PMID 30645009.
  33. ^ Buechley, E. R. & Şekercioğlu, Ç. H. (2016). "The avian scavenger crisis: Looming extinctions, trophic cascades, and loss of critical ecosystem functions". Biological Conservation. 198: 220–228. doi:10.1016/j.biocon.2016.04.001.
  34. ^ O'Bryan, C. J.; Holden, M. H. & Watson, J. E. M. (2019). "The mesoscavenger release hypothesis and implications for ecosystem and human well-being". Ecology Letters. 22 (9): 1340–1348. doi:10.1111/ele.13288. PMID 31131976. S2CID 167209009.
  35. ^ "Over 500 Rare Vultures Die After Eating Poisoned Elephants In Botswana". Agence France-Press. NDTV. 2019-06-21. Retrieved 2019-06-28.
  36. ^ Hurworth, Ella (2019). "More than 500 endangered vultures die after eating poisoned elephant carcasses". CNN. Retrieved 2019-06-28.
  37. ^ Solly, M. (2019). "Poachers' Poison Kills 530 Endangered Vultures in Botswana". Smithsonian. Retrieved 2019-06-28.
  38. ^ Ngounou, B. (2019). "Botswana: Over 500 vultures found dead after massive poisoning". Afrik21. Retrieved 2019-06-28.
  39. ^ Wilkinson, Richard H. (2003). The Complete Gods and Goddesses of Ancient Egypt. Thames & Hudson. pp. 213–214.
  40. ^ "The Ancient Egyptian Goddess of Pregnancy".
  41. ^ "Life Egyptian Vulture". 17 September 2018.
  42. ^ Benson, Elizabeth P. The Vulture: The Sky and the Earth.
  • Hilty, S. L. (2003). Birds of Venezuela. London: Christopher Helm Publishers. ISBN 978-0-7136-6418-8. OCLC 51031554.

External links

  • Vulture videos on the Internet Bird Collection
  • Ventana Wildlife Society
  • Vulture observatory in Spain
  • A Vulture Restaurant
  • Declining Vulture Count in India
  • Vulture Conservation in Western Coast of India
  • Website for journal Vulture News