Satellite pinpoints behaviour of rare vultures
BirdLife International and the Wildlife Conservation Society have announced a significant advance in the understanding and conservation of threatened vultures in Indochina.
Attempts to capture and study vultures in the dry forests landscape of northern Cambodia have proved challenging. Following a lengthy, concerted trapping effort in May 2005, WCS researchers were rewarded with the successful capture of five Critically Endangered vultures (three Slender-billed Vultures Gyps tenuirostris and two White-rumped Vultures Gyps bengalensis), as well as two near-threatened Red-headed Vultures Sarcogyps calvus. This trapping exercise was conducted while carrying out a “vulture restaurant” in Chhep District, Preah Vihear Province, northern Cambodia.
All birds were wing-tagged, leg-banded, and three birds (two Slender-billed and one White-rumped) were fitted with satellite transmitter units provided by the Royal Society for the Protection of Birds (BirdLife in the UK), before being released. Samples also were collected to determine the health status of the birds and their exposure to infectious disease.
"By fixing satellite transmitters and monitoring vulture movements, we develop a greater understanding of their range size, habitat preferences, and seasonal movements. This increased understanding of ecological parameters allows us to develop more effective, targeted conservation actions and management guidelines." —Dr Sean Austin, Manager of BirdLife International’s Cambodia Programme
Satellite tracking provides an accurate, up-to-date, landscape overview of vulture behaviour and ranging patterns. Maps of the three satellite tagged vultures from May 2005 show that all three birds left the trapping area soon after capture and settled quite close to each other approximately 80 km to east. The greatest distance was covered by the White-rumped Vulture which travelled considerably further than the others, drifting through five provinces. One of the Slender-billed Vultures travelled north at one point settling along the Mekong River in southern Laos.
Vultures are examples of what conservationists call “dispersed species” that range at low population densities over very large areas in search of food. Hunting of Cambodia’s wild ungulates has greatly reduced the availability of food for the vultures, forcing them to forage over wider areas, and exposing them to risks beyond the confines of limited protected areas.
Three species of Asian vultures (White-rumped Vulture Gyps bengalensis, Slender-billed Vulture Gyps tenuirostris, and Indian Vulture Gyps indicus) in South Asia have declined dramatically over the past decade and are now facing imminent extinction. Recorded population declines in India are over 97% since 1993 and 30-40% annually in Pakistan. Research has revealed that these declines are caused by veterinary use of the drug Diclofenac. All three of these vulture species are presently considered Critically Endangered. If the populations of these species in South Asia decline to extinction, only two small, disparate, wild populations of White-rumped and Slender-billed Vultures will remain; one in north-eastern Cambodia and southern Laos, and the other in Myanmar.