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Himalayan vulture

The Himalayan vulture (Gyps himalayensis) or Himalayan griffon vulture is an Old World vulture native to the Himalayas and foothills in North and Northeastern India, as well as the adjacent Tibetan Plateau. After the cinereous vulture (Aegypius monachus), it is the second-largest Old World vulture species, and among the world's largest true raptors. It is listed as Near Threatened on the IUCN Red List.[1] It is not to be confused with the Eurasian griffon vulture (Gyps fulvus), which is a visually similar, sympatric species.[3]

Himalayan vulture
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Gyps
Species:
G. himalayensis
Binomial name
Gyps himalayensis
Hume, 1869[2]

Description

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Adult spotted in Dhauladhar range
 
Juvenile in flight
Measurements
[4][5][6]
Length 1,030–1,150 mm (40.6–45.3 in)
Culmen 71–77 mm (2.8–3.0 in)
Wing 755–805 mm (29.7–31.7 in)
Tail 355–405 mm (14.0–15.9 in)
Tarsus 110–126 mm (4.3–5.0 in)

The Himalayan vulture has dark brown greater covert feathers, tail and wing quills, but a pale buff uniform upperside and paler tipped inner secondaries; its legs are covered with buffy feathers and vary in colour from greenish grey to pale brown. The underside and under-wing coverts are pale brown or buff, almost white in some individuals. The whitish down on the head of immatures changes to yellowish in adults who have a long and pale brown ruff with white streaks and long and spiky ruff feathers.[6]

The pale blue facial skin is lighter than the dark blue in Gyps fulvus with this species having a yellowish bill. In flight the long fingers are splayed and there is a pale patagial stripe on the underwing. The wing and tail feathers are dark and contrast with the pale coverts and body, one of the best methods to distinguish this species from the slightly smaller griffon vulture.[4][7] The feathers on the body have pale shaft streaks.[6][8][9]

It is the largest of the Gyps species, averaging larger in every method of measurement than its relatives, and is perhaps the largest and heaviest bird in the Himalayas.[5] Weight in Himalayan vultures ranges from 6 kg (13 lb)[10] to 12.5 kg (28 lb).[11] It has been estimated to weigh an average of 9 kg (20 lb), but weights vary with conditions from 8–12 kg (18–26 lb).[5][12][13] Published measurements of the wingspan vary from 2.56 to 3.1 m (8 ft 5 in to 10 ft 2 in), a similar range to that of cinereous vulture,[5][6] but the wingspan varies greatly depending on the method used to measure them.[14]

It differs from the similar-coloured Indian vulture (G. indicus) by a stouter, more robust bill; younger birds have a pale bill and tend to have buffy-white streaks on the scapulars and wing coverts contrasting with dark brown underparts.[6] It is similar in size to the cinereous vulture (Aegypius monachus), which typically has a slightly shorter overall length but can weigh more than the Himalayan vulture.[5][15]

Distribution

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Himalayan griffons in Spiti

The Himalayan vulture lives mainly in the higher regions of the Himalayas and the Tibetan Plateau at the elevation range of 1,200–5,500 m (3,900–18,000 ft). It is distributed from Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, Afghanistan and Iran to Pakistan to India, Nepal, Bhutan to western China and Mongolia.[1] Juvenile birds may however disperse further south, and vagrants have been recorded in Thailand, Burma, Singapore and Cambodia.[16]

Behaviour and ecology

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Diet

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The Himalayan vulture perches on crags, favourite sites showing white marks from regular defecation. They tend to not range below an elevation of 1,215 m (3,986 ft).[6] Himalayan vultures often bask in the sun on rocks. They soar in thermals and are not capable of sustained flapping flight. Flocks may follow grazers up the mountains in their search for dead animals. This vulture makes a rattling sound when descending on a carcass and can grunt or hiss at roosts or when feeding on carrion.[4] While feeding, individuals may make cackling sounds to defend their food from other vultures or even reprimand them. They are social birds, and are hence found in large flocks, while even being accompanied by crows (observed with other vulture species as well). Such crows cannot interfere with the flocks (as vultures are physically larger and stronger than crows), but vehicular traffic, human interference, and attacks from herding dogs can pose a disturbance.

They have been recorded eating carrion exclusively, some which is fed on even when putrid.[6] On the Tibetan Plateau, it was noted that 64% of their diet was obtained from deceased domestic yak (Bos grunniens).[17] The birds fed on old carcasses, sometimes even waiting for several days near a dead animal.[4][18] However, each vulture species has a specialty diet: Himalayan vultures largely disdain offal (which is readily eaten by other vulture species), typically eating only fleshy tissue.[6] Historically, Himalayan vultures regularly fed on human corpses left out on Celestial burial grounds.[6]

The Himalayan vulture is fairly defensive around other scavengers, such as foxes or smaller felines, and typically dominates other meat-eaters at carcasses, though it is subservient to gray wolves (Canis lupus), snow leopards (Panthera uncia) and cinereous vultures (Aegypius monachus).[6] In a large party, these vultures can reportedly strip a carcass of all tissue in 30 minutes, and do the same to a yak carcass in roughly 120 minutes.[6] Himalayan vultures have been observed feeding on pine (Pinus roxburghii) needles, an unexplained behaviour that cannot be for obtaining nutrition, but may be done to access essential oils and terpenes in the needles for digestive or immunity benefits.[19]

Breeding

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The breeding season begins in January. The nest is a platform of sticks placed on an inaccessible ledge on a cliff. Nest in northeastern India have been recorded at between 1,215 and 1,820 m (3,986 and 5,971 ft) in elevation, but those in Tibet have been as high as 4,245 m (13,927 ft).[6] Several pairs may nest on the same cliff face, with between five and seven pairs being a typical colony size.[6] The nests are relatively small for the large size of these birds and, although grow larger with repeated uses, do not generally get as massive as the nest of other large accipitrids.[6] There is at least one recorded instance of Himalayan vultures using a nest made by bearded vultures (Gypaetus barbatus).[6] On the Tibetan Plateau, Himalayan and bearded vultures were observed nesting in close proximity without conflict, which is notable because in several other cases of adjacent interspecies nesting by Old World vultures (including some involving bearded vultures) have resulted in high aggression and interspecies attacks.[20] A single white egg marked with red splotches is the usual clutch.[18] Egg laying dates in northern India have ranged from December 25 to March 7.[6] The egg is coarse and oval and can measure from 87 to 103.6 mm (3.43 to 4.08 in) in height and 65 to 74 mm (2.6 to 2.9 in) in width, with an average of 94.8 by 70.1 mm (3.73 by 2.76 in).[6] In captivity the incubation period was about 54–58 days. The young birds stay on with the parents for six to seven months.[21]

Threats

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See also: Indian vulture crisis
 
Himalayan vultures in Jalpaiguri, West Bengal
 
Himalayan griffon near Jalpaiguri

Himalayan vultures are susceptible to toxicity induced by diclofenac, a drug whose residues in domestic animal carcasses has led to rapid declines in populations of other Gyps vultures across Asia.[22] The Himalayan griffon vulture populations have however not shown signs of rapid decline,[17] although reductions in nesting birds have been noted in some parts of its range in Nepal.[23][24]

References

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  1. ^ a b c BirdLife International (2017). "Gyps himalayensis". IUCN Red List of Threatened Species. 2017: e.T22695215A118594518. doi:10.2305/IUCN.UK.2017-3.RLTS.T22695215A118594518.en. Retrieved 19 November 2021.
  2. ^ Hume, A.O.H. (1869). "Gyps fulvus, Gmel. (Gyps himalayensis, nobis.)". My scrap book: or rough notes on Indian oology and ornithology. Calcutta: C.B. Lewis, Baptist Mission Press. pp. 12–18.
  3. ^ Ram, Mohan; Sahu, Aradhana; Tikadar, Shyamal; Gadhavi, Devesh; Rather, Tahir Ali; Jhala, Lahar; Zala, Yashpal (December 2022). "MDPI-Home Range, Movement and Activity Patterns of Six Vulture Species". Ecologies. 3 (4): 492–507. doi:10.3390/ecologies3040035.
  4. ^ a b c d Rasmussen, P.C. & Anderton, J.C. (2005). Birds of South Asia, The Ripley Guide. Vol. 2. Washington DC and Barcelona: Smithsonian Institution and Lynx Edicions. pp. 90–91.
  5. ^ a b c d e Ferguson-Lees, J. & Christie, D. (2001). Raptors of the World. Helm Identification Guides. London: Christopher Helm. pp. 717–719. ISBN 0-7136-8026-1.
  6. ^ a b c d e f g h i j k l m n o p q Brown, L. & Amadon, D. (1986). Eagles, Hawks and Falcons of the World. The Wellfleet Press. ISBN 978-1555214722.
  7. ^ Alström, P. (1997). "Field identification of Asian Gyps vultures". OBC Bull. 25: 32–49.
  8. ^ Baker, E.C.S. (1928). The Fauna of British India: Birds. Vol. 5 (2nd ed.). Taylor and Francis. pp. 13–15.
  9. ^ Blanford, W.T. (1895). "Gyps himalayensis. The Himalayan Griffon". The Fauna of British India. Vol. 3. Birds. London: Taylor and Francis. p. 321.
  10. ^ Barathidasan, R.; Singh, S.D.; Saini, M.; Sharma, A. & Dhama, K. (2013). "The first case of angioinvasive pulmonary aspergillosis in a Himalayan Griffon Vulture (Gyps himalayensis)". Avian Biology Research. 6 (4): 302–306. doi:10.3184/175815513X13818257354160. S2CID 87695235.
  11. ^ Grzimek, B.; Schlager, N.; Olendorf, D. & McDade, M.C. (2004). Grzimek's Animal Life Encyclopedia. Vol. Volume 8: Birds. Farmington Hills, Michigan: Gale.
  12. ^ Namgail, T. & Yom-Tov, Y. (2009). "Elevational range and timing of breeding in the birds of Ladakh: the effects of body mass, status and diet" (PDF). Journal of Ornithology. 150 (2): 505–510. Bibcode:2009JOrni.150..505N. doi:10.1007/s10336-008-0369-8. S2CID 29756171.
  13. ^ Schlee, M.A. (1989). "Breeding the Himalayan griffon Gyps himalayensis at the Paris menagerie". International Zoo Yearbook. 28: 234–240. doi:10.1111/j.1748-1090.1989.tb03288.x.
  14. ^ Winker, K. (1998). "Suggestions for measuring external characters of birds" (PDF). Ornitologia Neotropical. 9: 23–30.
  15. ^ Del Hoyo, J.; Elliot, A. & Sargatal, J. (1996). Handbook of the Birds of the World. Vol. 3. Barcelona: Lynx Edicions. ISBN 84-87334-20-2.
  16. ^ Li, D.L. & Kasorndorkbua, C. (2008). "The status of the Himalayan Griffon Gyps himalayensis in South-East Asia". Forktail. 24: 57–62.
  17. ^ a b Lu, X.; Ke, D.; Zeng, X.; Gong, G. & Ci, R. (2009). "Status, Ecology, and Conservation of the Himalayan Griffon Gyps himalayensis (Aves, Accipitridae) in the Tibetan Plateau". Ambio: A Journal of the Human Environment. 38 (3): 166–173. Bibcode:2009Ambio..38..166L. doi:10.1579/0044-7447-38.3.166. PMID 19580034. S2CID 22551672.
  18. ^ a b Ali, S. & Ripley, S.D. (1978). Handbook of the birds of India and Pakistan. Vol. 1 (Second ed.). New Delhi: Oxford University Press. pp. 302–304.
  19. ^ Atkore, V. M. & Dasgupta, S. (2006). "Himalayan Griffon Gyps himalayensis feeding on chir pine Pinus roxburghii needles". Indian Birds. 2 (6).
  20. ^ Katzner, T.E.; Lai, C.H.; Gardiner, J.D.; Foggin, J.M.; Pearson, D. & Smith, A.T. (2004). "Adjacent nesting by Lammergeier Gypaetus barbatus and Himalayan griffon Gyps himalayensis on the Tibetan Plateau, China". Forktail. 20: 94–96.
  21. ^ Schlee, M.A. (1989). "Breeding the Himalayan griffon Gyps himalayensis at the Paris Menagerie". International Zoo Yearbook. 28: 234–240. doi:10.1111/j.1748-1090.1989.tb03288.x.
  22. ^ Das, D.; Cuthbert, R.J.; Jakati, R.D. & Prakash, V. (2011). "Diclofenac is toxic to the Himalayan Vulture Gyps himalayensis". Bird Conservation International. 21 (1): 72–75. doi:10.1017/S0959270910000171.
  23. ^ Acharya, R.; Cuthbert, R.; Baral, H.S. & Shah, K.B. (2009). "Rapid population declines of Himalayan Griffon Gyps himalayensis in Upper Mustang, Nepal" (PDF). Bird Conservation International. 19: 99–107. doi:10.1017/S0959270908007417.
  24. ^ Virani, M.Z.; Giri, J.B.; Watson, R.T. & Baral, H.S. (2008). "Surveys of Himalayan Vultures (Gyps himalayensis) in the Annapurna Conservation Area, Mustang, Nepal" (PDF). Journal of Raptor Research. 42 (3): 197–203. doi:10.3356/JRR-07-35.1. S2CID 52059532.
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