Pamela Rasmussen's interest in Asian birds led to her involvement in more specifically conservation-directed projects. Two "Gyps" vultures, the Indian white-rumped vulture, "Gyps bengalensis", and the "long-billed vulture" suffered a 99 percent population decrease in South Asia due to poisoning by diclofenac, a veterinary drug that causes kidney failure in birds that have eaten the carcasses of treated cattle. Rasmussen showed that there are two distinct species of long-billed vulture: the Indian vulture "G. indicus" and slender-billed vulture "G. tenuirostris". This is important to conservation, since a captive-breeding program has been established to assist the recovery of at-risk vulture species.