Thered-headed vulture (Sarcogyps calvus), also known as theAsian king vulture,Indian black vulture orPondicherry vulture,[2] is anOld World vulture mainly found in theIndian subcontinent, with small disjunct populations in some parts ofSoutheast Asia.
It is a medium-sized vulture of 76 to 86 cm (30 to 34 in) in length, weighing 3.5–6.3 kg (7.7–13.9 lb) and having awingspan of about 1.99–2.6 m (6.5–8.5 ft).[3][4] It has a prominent naked head: deep-red to orange in the adult, paler red in the juvenile. It has a black body with pale grey band at the base of the flight feathers. The sexes differ in colour of the iris: males have a paler, whitish iris, whilst in females it is dark brown.[5]
The red-headed vulture is very similar in appearance to its larger relative theLappet-faced vulture inAfrica andArabia, even being historically placed in the genus Torgos[6]
A female red-headed vulture (left) and aLappet-faced vulture (right). Both have similar anatomical features including skull shapes and the dangling skin lappets. They are believed to be closely related
This gaudy-facedvulture was historically abundant, range widely across the Indian subcontinent, and also eastwards to south-central and south-eastern Asia, extending fromIndia toSingapore. Today the range of the red-headed vulture is localized primarily to northern India. It is usually in open country and in cultivated and semi-desert areas. It is also found in deciduous forests and foothills and river valleys. It is usually found up to an altitude of 3000m from sea level.[7]
The red-headed vulture used to be declining, but only slowly; in 2004 the species was uplisted tonear threatened fromleast concern by theIUCN. The widespread use of theNSAIDdiclofenac inveterinary medicine in India has caused its population to collapse in recent years, however. Diclofenac is a compound now known to be extremely poisonous to vultures. The red-headed vulture population has essentially halved every other year since the late 1990s, and what once was a plentiful species numbering in the hundreds of thousands has come dangerously close toextinction in less than two decades. Consequently, it was uplisted to critically endangered in the 2007IUCN Red List.[1]
Several NSAIDs have been found to be harmful to scavenging birds. Diclofenac,carprofen,flunixin, ibuprofen and phenylbutazone were associated with mortality.Meloxicam has thus far been found to be "Vulture-Safe" and its use in veterinary treatment of livestock is being encouraged.[8][9]
The red-headed vulture has become increasingly difficult to find due to hunting. In places like Cambodia, special programs have been implemented to support critically endangered vulture species. Evidence has shown that hunters have started using poisons in their hunting practices.[10] Population analysis indicates that since 2010, populations of the White-rumped Vulture (Gyps bengalensis) and Red-headed Vulture (Sarcogyps calvus) have declined, while the Slender-billed Vulture (Gyps tenuirostris) may have also begun to decline since 2013.[10]
In an assessment made in 2021 assessed there are 2500-9999 mature individuals in the wild.[1]
A significant factor in the rapid decline of Red-headed Vulture populations since the 21st century is the pharmaceutical NSAID diclofenac, used to treat livestock. This substance has proven highly toxic to vultures, leading to mortality from renal failure and visceral gout. Recent findings indicate that Red-headed Vulture populations in India have shown signs of recovery following a ban on diclofenac, suggesting the drug's adverse effects on the species.[1]
Incidental mortality occurs in Cambodia due to the widespread use of poisons for catching fish or waterbirds at trapeangs (waterholes). Intentional poisoning for belief-based use has also been reported in Cambodia. Additionally, the logging of nesting trees, electrocution, and collisions with powerlines are potential threats to the species.[1]
In the shared ecosystem, dominant vulture species like Gyps vultures have a competitive advantage in scavenging on carcasses. They typically outcompete the Red-headed Vulture for access to food resources, which can lead to food scarcity for the species. As a result, the Red-headed Vulture may have limited access to suitable feeding opportunities, potentially affecting its survival and contributing to its population decline.[1]
^Milius, Susan (4 February 2006). [tp://www.sciencenews.org/view/generic/id/7025/title/Bird-Safe_Rx_Alternative_drug_wont_kill_Indias_svultures "Bird-Safe Rx: Alternative drug won't kill India's vultures"].ScienceNews.169 (#5): 70. Retrieved11 May 2011.