Bald vulture
| Bald vulture | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Bald headed vulture in Corbett National Park ( India ) |
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name of the genus | ||||||||||
| Sarcogyps | ||||||||||
| Lesson , 1842 | ||||||||||
| Scientific name of the species | ||||||||||
| Sarcogyps calvus | ||||||||||
| ( Scopoli , 1786) |
The bald vulture ( Sarcogyps calvus ) or lavender is a medium-sized species of the Old World vulture (Gypinae). The genus Sarcogyps is monotypical with the bald vulture as the only species.
description
Bald-headed vultures are medium-sized and quite powerfully built Old World vultures. The long, relatively narrow wings are widest at the base and sharply pointed towards the end. The hand wings are fingered with medium strength. The tail is short and slightly wedge-shaped in the fresh plumage, but rounded in the worn plumage. The species shows minimal sexual dimorphism in size and weight, males reach an average of 98% of the dimensions of females. The body length is 76–86 cm, the wingspan 199–227 cm, the weight 3.7–5.4 kg and the wing length 570–625 mm.
In terms of coloration, the sexes do not differ, but the eye color is different in males and females. This vulture is predominantly black in adult plumage . The lower back and rump as well as the bases of the arm wings are lighter and more brown. The white breasts at the base of the neck and the oval white fields of the upper leg fletching contrast strongly with the other dark plumage. The head and neck are largely featherless and intensely yellowish red or orange-red, on the sides of the head there are large, equally colored skin flaps. When excited, these areas of the skin turn brighter red. The weakly pronounced, downy ruff is black on the sides of the neck and on the nape of the neck.
The high and strong beak is dark brown, the wax skin , like the head, is yellowish red or orange-red. The iris is yellowish white to yellow in males and reddish brown to dark red in females. The legs are dull red.
Young birds are overall significantly lighter than adults. When young, the entire upper side of the trunk including the rump and the upper wing-coverts are medium brown with light feather edges. The underside is overall lighter brown. The wings and control springs are darker and more blackish. The upper chest, lower flanks, inner and outer upper leg fletching, as well as the lower abdomen and lower tail-coverts are white. The head and neck are paler, the closed white downy feathering of the top of the head is reduced to the throat and to the sides of the neck to individual downy areas. The skin flaps are still missing, there are only a few loose skin folds on the sides of the head. Bald vultures are likely to be colored by the age of 5 years.
Bald vultures can take off from the ground relatively easily with a few slow but deep flaps of their wings. In gliding the wings are only raised very slightly, in gliding they are held horizontally and the hand wing is bent downwards.
Systematics
The genus Sarcogyps is monotypical with the bald vulture as the only species. The intra-species variability is low and no subspecies are recognized.
Vocalizations
The vultures of the species are similar to those of other Old World vultures and are described as squeaks, hisses and grunts. When fighting on the carcass, the animals utter hoarse croaking noises that can increase to "a kind of screeching". Bald-headed vultures utter a loud roar during courtship and copulation.
distribution
The original distribution area covered large parts of South and Southeast Asia. It stretched from the southern edge of the Himalayas in Pakistan, India, Nepal and Bhutan to the south across most of the Indian subcontinent . In addition, the area of the species encompassed almost all of Indochina from the north of Myanmar and southwest China to the southern tip of Vietnam and with scattered occurrences also extended to the south of the Malay Peninsula .
In the last few decades the range of the bald vulture has shrunk considerably. The species is now absent in almost the entire southern half of the Indian subcontinent and in its west. In Indochina there are only small and heavily isolated deposits. The size of the total distribution area was estimated in 2012 at 3.69 million km².
habitat
The species inhabits a wide range of semi-open and open habitats from dry forests and dense tree savannahs to semi-deserts, river valleys, coasts and agricultural areas. Bald-headed vultures occur from sea level up to 1500 m, locally up to 2500 m.
Way of life
behavior
This vulture often sits freely on a tree top, less often on rocks or buildings.
Foraging and Nutrition
The search for food takes place mostly in high circles. Bald vultures can also circling low over bushfires for a long time, only to land on small vertebrates that have been killed by the fire. This vulture occasionally hunts smaller vultures such as the Egyptian vulture for food. Species of the genus Gyps such as the Bengal vulture ( Gyps bengalensis ) and the lesser-billed vulture ( Gyps tenuirostris ) tend to dominate large carrion compared to the bald vulture. The diet consists of carrion of all sizes, including small animals.
Reproduction
Bald vultures live in single territorial pairs. The courtship consists of common circles and "tandem flights" in which one partner copies every flight movement of the other bird, as well as sometimes spectacular swoops, turns in the air and mutual grabbing of the catches.
The nests are often built in agricultural areas or other open landscapes and mostly in large trees at a height of 10–30 m, occasionally also in the forest and in semi-deserts, in the absence of other possibilities, only on a bush at a height of 1–3 m.
Newly built nests are often quite small and only 40 to 65 cm in diameter and 15 cm high; however, old and repeatedly used nests can reach a diameter of up to 1.5 m and a height of 1.2 m. The nests consist of sticks and twigs and are covered with straw, remains of carrion and rubbish. Laying begins mainly between February and March, and the clutch consists of one egg. The breeding season lasts about 45 days, the duration of the nestling period is not yet known.
Existence and endangerment
In Indochina, the species used to be widespread and mostly common, but in the last few decades the population there has declined sharply and the range has also shrunk considerably. Since there are still large areas of habitats suitable for the species in Indochina, the decline there is mainly attributed to the decline in large wild mammals and improved housing conditions for domestic animals, both of which have led to a greatly reduced supply of carrion. Today the population in Indochina is estimated at only a few hundred individuals.
From around 1999 the species suffered a catastrophic population collapse on the Indian subcontinent, in India the population decreased by 94% percent between 2000 and 2003. The main cause of this population collapse is the widespread use of the anti-inflammatory drug diclofenac for the treatment of injuries and infections in domestic cattle and water buffalo ; Diclofenac is highly poisonous for the bald vulture as well as for the Old World vultures of the genus Gyps . The Indian government has passed a law banning the manufacture of diclofenac for veterinary purposes, this law stipulated that its use was suspended until the end of 2005. In 2007, however, diclofenac was still in widespread use in India and, according to the IUCN, will likely remain so for several years. Nepal and Pakistan have also passed regulations banning the manufacture and import of diclofenac.
Due to the extremely negative population development and the small remaining world population of probably no more than 10,000 specimens, the IUCN classifies the species as critically endangered worldwide.
swell
Individual evidence
- ^ J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London, 2001: pp. 120 and 445.
- ^ J. Ferguson-Lees, DA Christie: Raptors of the World. Christopher Helm, London, 2001: p. 444.
- ↑ a b c d e Sarcogyps calvus in the endangered Red List species the IUCN 2012. Posted by: BirdLife International, 2009. Accessed February 25 2012th
- ↑ The Bald Vulture at BirdLife International . Retrieved March 1, 2012.
- ↑ Rhys E. Green, Ian Newton, Susanne Shultz, Andrew A. Cunningham, Martin Gilbert, Deborah J. Pain, Vibhu Prakash 2004: Diclofenac poisoning as a cause of vulture population declines across the Indian subcontinent. Journal of Applied Ecology 41, Volume 5: pp. 793-800.
literature
- James Ferguson-Lees , David A. Christie: Raptors of the World. Christopher Helm, London 2001, ISBN 0-7136-8026-1 , pp. 120-121 and 443-445.
Web links
- Sarcogyps calvus in the endangered Red List species the IUCN 2012. Posted by: BirdLife International, 2009. Accessed February 25 2012th
Other web links
- Videos, photos and sound recordings on Sarcogyps calvus in the Internet Bird Collection