Egyptian Vulture

Egyptian Vulture
Adult N. p. ginginianus
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Neophron
Savigny, 1809
Species: N. percnopterus
Binomial name
Neophron percnopterus
(Linnaeus, 1758)
Distribution of the populations, birds breeding in Europe winter in Africa

The Egyptian Vulture (Neophron percnopterus) is a small Old World vulture, found widely distributed from southwestern Europe and northern Africa to southern Asia. It is the only living member of the genus Neophron. It has sometimes also been known as the White Scavenger Vulture or Pharaoh's Chicken. Like other vultures it soars on thermals and the underwing black and white pattern and wedge tail make it distinctive. It sometimes uses stones to break the eggs of birds making it one of the few birds that make use of tools. Birds that breed in the temperate region migrate south in winter while tropical populations are relatively sedentary. Populations of this species have declined in the 20th Century and some isolated island forms are particularly endangered.

Contents

Taxonomy and systematics

The genus Neophron contains only a single species. A few prehistoric species from the Neogene of North America placed in the genus Neophrontops (the name meaning "looks like Neophron") are believed to have been very similar to these vultures in lifestyle but the relationships are unclear.[2][3] The genus is considered to be among the oldest branching species within the vultures and the closest living relative is the Lammergeier (Gypaetus barbatus).[4][5] Some authors have suggested that they should be placed in a separate subfamily, the Gypaetinae.[6] There are three widely recognised subspecies of the Egyptian Vulture although there is considerable gradation due to movement and intermixing of the populations.[7] A subspecies rubripersonatus from Baluchistan and the northwestern Himalayas (said to have a dark bill with a yellowish tip) described by Nikolai Zarudny and Härms is rarely recognized.[8][9][10]

The genus name is derived from Greek mythology. Neophron was the son of Timandra, the mistress of Aegypius. Neophron tricked Aegypius into sleeping with his own mother Bulis imagining it was Timandra. When the deception was found, Bulis sought to take out the eyes of her son but Zeus changed Aegypius and Neophron into vultures.[14] The species name refers to the black wings ("περκνóς" =blue-black +"πτερόν"=wing).[15]

Description

The adult plumage is white, with black flight feathers in the wings. The white plumage however usually appears soiled due to the habits of the birds. The bill is slender and long and the tip of the upper mandible is hooked. The nostril is an elongated horizontal slit. The feathers on the neck are long and form a hackle. The wings are pointed with the third primary being the longest. The tail is wedge shaped. The claws are long and straight and the 3rd and 4th toes are slightly webbed at the base. The bill is black in the nominate population but is pale or yellowish in the smaller Indian ginginianus, but this variation may need further study.[9] The facial skin is yellow and crop is unfeathered.[16] Young birds are blackish or chocolate brown with black and white patches.[16]

The adult Egyptian Vulture measures 47–70 cm (21–28 in) from the point of the beak to the extremity of the tail feathers and 1.5-1.7 metre (5-5.6 ft) between the tips of the wings. In N. p. ginginianus males are about 47.5-52.5 cm long while females are 52-55.5 cm long.[9] It weighs about 2 kilograms (4.4 lbs) although birds of the subspecies majorensis average 2.4 kilograms (5.3 lbs), about 18% heavier than birds from Iberia.[17]

Distribution

Egyptian Vultures are widely distributed and may be found in southern Europe, in northern Africa, and in western and South Asia. Their habitat is mainly in the dry plains and nest mainly in arid and rocky hill regions. It is a rare vagrant in Sri Lanka.[16] Vagrants are sometimes found further north in Europe and in South Africa.[18] European populations have been recorded migrating south into Africa about 3500 to 5500 km, sometimes covering nearly 500 km in a single day. A bird that bred in France migrated south only in its third year.[19][20] Like many other soaring diurnal migrants, they avoid making long crossings over water.[21] Italian birds cross over through Sicily and into Tunisia over the islands of Marettimo and Pantelleria.[22]

Behaviour and ecology

This species is often seen soaring in thermals often with other scavengers. They feed on a range of food including mammal faeces (especially human[23]), insects in dung, carrion as well as vegetable matter and sometimes small live prey.[24] Studies suggest that feeding on mammalian (in this case, ungulate) faeces helps in obtaining carotenoid pigments responsible for the bright yellow and orange facial skin.[25] They are usually silent but near the nest they make high-pitched mewing or hissing notes.[9]

They roost communally[26] and nests are often traditionally used year after year. Birds are however usually seen singly or in pairs. They are socially monogamous and pair bonds may be maintained for more than one breeding season. Extra-pair copulation with neighbouring birds is however noted and adult males tend to stay close to the female before and during the egg laying period.[27] The nest sites include cliffs, buildings as well as trees.[9] Unusual nest sites such as on the ground have been recorded in N. p. ginginianus and N. p. majorensis.[28][29][30] The nesting season is February to April in India. Both parents incubate and the two eggs hatch after about 42 days.[16] The second chick may hatch after an interval of 3 to 5 days or more. The longer the interval, the more likely is the death of the second chick due to starvation.[31] In areas where nests are close to each other, young birds may sometimes move to neighbouring nests to obtain food.[32] In the Spanish population, young fledge and leave the nest after 90 to 110 days.[33] Young birds disperse from their nest site and birds in Spain have been recorded to move nearly 500 km away from their nest site.[34][35] The full adult plumage is attained in the fourth or fifth year. In captivity, birds have been known to live for up to 37 years.[36]

Healthy adults do not have any predators but mortality from powerlines, pollution and poisoning have been noted. Young birds have been known to be taken by Golden Eagles, Eagle Owls and Red Fox. Birds falling off the cliffs may be picked up by Jackals.[37]

The nominate population, especially in Africa is well known for their use of stones as tools. When a large egg, such as that of an ostrich or bustard is located, the bird approaches it with a large pebble held in the bill and tosses it by standing near the egg and swinging the neck down. The operation is repeated until the egg cracks from the blows.[38] This behaviour has not been recorded in N. p. ginginianus.[9] Tests with hand-reared and wild birds suggest that the behaviour is shown by naive birds raised alone in captivity (and therefore not learnt from observing other birds) and is displayed once they associate eggs with food. They show a strong preference for rounded pebbles rather than jagged rocks.[39] Bulgarian birds have been observed to use twigs to roll up and gather strands of wool that they make use of in their nest lining.[40]

Conservation status

The Egyptian Vulture is declining in large parts of its range, often severely. In Europe and most of the Middle East, it is half as plentiful as it was about twenty years ago, and the populations in India and southwestern Africa have greatly declined. In 1967-70, the area around Delhi was estimated to have 12000-15000 of these vultures with an average density of about 5 pairs per 10 km2.[41][42] The cause of the decline is not known but has been linked with the use of the NSAID Diclofenac which has been known to cause death in Gyps vultures.[43] In southern Europe, suggested causes of the decline include poisoning by accumulation of lead, pesticides (especially due to large-scale use in the control of Schistocerca gregaria locust swarms) and by electrocution.[17][44] Studies in Spain have suggested that the absorption of veterinary antibiotics suppresses their innate immunity, making them more prone to infection.[45]

The population in the Canary Islands have been isolated from populations in Europe and Africa for a significant period of time and have declined greatly and are of particular concern due to their genetic distinctiveness. The Canarian Egyptian Vulture was historically common, occurring on the islands of La Gomera, Tenerife, Gran Canaria, Fuerteventura and Lanzarote. It is now restricted to Fuerteventura and Lanzarote, the two easternmost islands. The total population in 2000 was estimated at about 130 individuals, including 25–30 breeding pairs.[17][46] The island birds appear to be more susceptible to infections.[47] Island birds appear to accumulate significant amounts of lead from scavenging on hunted animal carcasses and the long-term effect of this poison at a sublethal level is not known although it alters the mineralization of their bones.[48] In order to provide safe and uncontaminated food for nesting birds, attempts have been made to create "vulture restaurants" where carcasses are made available. These interventions however may also encourage opportunist predators and scavengers to concentrate at the site and pose a threat to nesting birds in the vicinity.[49]

In culture

Egyptian Vulture
in hieroglyphs

In Ancient Egypt, the vulture hieroglyph was the uniliteral sign used for the glottal sound (3). The Hebrew word rachamah/racham used in the Bible and translated into English as gier-eagle refers to this species.[15][50] The bird was held sacred to Isis. The association of the vulture as a symbol of royalty in Egyptian culture led to the use of the name "Pharaoh's Chicken" for the species.[51][52]

A southern Indian temple at Thirukalukundram near Chengalpattu is famed for a pair of birds that have reputedly visited the site for "centuries". These birds are traditionally fed by the temple priests and arrive before noon to feed on offerings made from rice, wheat, ghee and sugar. Although punctual, the failure of the birds to turn up was attributed to the presence of "sinners" among the onlookers.[16][53][54] Legend has it the vultures (or "eagles") represent eight sages who were punished by Shiva with two of them leaving in each of a series of epochs.[55][56]

The habit of coprophagy has led to the Spanish names of "churretero" and "moñiguero" which mean "dung-eater".[25] British naturalists in colonial India considered them among the ugliest birds and their habit of feeding on faeces was particularly despised.[57]

Footnotes

  1. ^ IUCN redlist.
  2. ^ Feduccia 1974.
  3. ^ Hertel 1995.
  4. ^ Wink 1995.
  5. ^ Wink, Heidrich & Fentzloff 1996.
  6. ^ Seibold & Helbig 1995.
  7. ^ a b Donázar et al. 2002b.
  8. ^ Zarudny & Härms 1902.
  9. ^ a b c d e f Rasmussen & Anderton 2005.
  10. ^ Hartert 1910.
  11. ^ Pittie 2004.
  12. ^ Kretzmann et al. 2003.
  13. ^ Agudo et al. 2010.
  14. ^ Grimal 1996.
  15. ^ a b Koenig 1907.
  16. ^ a b c d e Ali & Ripley 1978.
  17. ^ a b c Donázar et al. 2002a.
  18. ^ Mundy 1978.
  19. ^ Meyburg et al. 2004.
  20. ^ García-Ripollés, López-López & Urios 2010.
  21. ^ Yosef & Alon 1997.
  22. ^ Agostini et al. 2004.
  23. ^ Whistler 1949.
  24. ^ Prakash & Nanjappa 1988.
  25. ^ a b Negro et al. 2002.
  26. ^ Donázar, Ceballos & Tella 1996.
  27. ^ Donázar, Ceballos & Tella 1994.
  28. ^ Biddulph 1937.
  29. ^ Paynter 1924.
  30. ^ Gangoso 2005.
  31. ^ Donázar & Ceballos 1989a.
  32. ^ Donázar & Ceballos 1990.
  33. ^ Donázar & Ceballos 1989b.
  34. ^ Elorriaga et al. 2009.
  35. ^ Ceballos & Donázar 1990.
  36. ^ Grande et al. 2009.
  37. ^ Stoyanova & Stefanov 1993.
  38. ^ van Lawick-Goodall & van Lawick-Goodall 1966.
  39. ^ Thouless, Fanshawe & Bertram 1989.
  40. ^ Stoyanova, Stefanov & Schmutz 2010.
  41. ^ Galushin 2001.
  42. ^ Galushin 1975.
  43. ^ Cuthbert et al. 2006.
  44. ^ Hernández & Margalida 2009.
  45. ^ Lemus & Blanco 2009.
  46. ^ Palacios 2004.
  47. ^ Gangoso et al. 2009b.
  48. ^ Gangoso et al. 2009a.
  49. ^ Cortés-Avizanda et al. 2009.
  50. ^ Coultas & Harland 1876, p. 138.
  51. ^ Ingerson 1923, p. 34.
  52. ^ Thompson 1895, p. 48.
  53. ^ Neelakantan 1977.
  54. ^ Siromoney 1977.
  55. ^ Pope 1900, p. 260.
  56. ^ Thurston 1906, p. 252.
  57. ^ Dewar 1906.
Cited works

External links