The Slender-billed Vulture (Gyps tenuirostris) is a recently recognized species of Old World vulture. For some time, it was lumped with its relative the Indian Vulture under the name of "Long-billed Vulture". However, these two species have parapatric or allopatric ranges and can be immediately told apart by trained observers, even at considerable distances.
This species has suffered a marked decline in its numbers in recent years. Wild populations remain from northern and eastern India through southern Nepal and Bangladesh, with a small population in Burma. The only breeding colony in Southeast Asia is in the Steung Treng province of Cambodia. This colony is thought to number about 50"?100 birds. The survival of the vultures in Cambodia may have been partly because diclofenac, which is poisonous to vultures, is not available there.
The Slender-billed Vulture is a protected species listed on the appendix II list of CITES, because its numbers have declined rapidly. Its decline is largely due to the use of the non-steroidal anti-inflammatory drug (NSAID) diclofenac in working farm animals, especially in India. Diclofenac is poisonous to vultures, causing kidney failure, and is being replaced by meloxicam (another NSAID), which is not toxic to Vultures.
Captive-breeding programs in India are aiming to conserve the species, and it is hoped that vultures can be released back in the wild when the environment is free of diclofenac.