of its relatives, lacks the white ring around the eye which give this group of birds its name. Rasmussen noted that the Togian white-eye is distinctive not only in its appearance, but also in its lilting song, which sounds higher pitched and is less varied in frequency than the songs of its close relatives. 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. Biodiversity In 2005, Rasmussen was part of a large multi-institutional collaboration investigating biodiversity hotspots, which have a prominent role in conservation. The study assessed locations quantitatively for three criteria of bird diversity – species richness, the level of threat, and the number of endemic species. The results demonstrated that hotspots did not show the same geographical distribution for each factor. Only 2.5% of hotspot areas are common to all three aspects of diversity, with over 80% of hotspots registering on only one criterion. Each criterion explained less than 24% of the variation in the other factors, suggesting that even within a single taxonomic class, different mechanisms are responsible for the origin and maintenance of various aspects of diversity. Consequently, the different types of hotspots also vary greatly in their utility as conservation tools. Rasmussen's recent work has concentrated on further large-scale collaborations with the same group of institutions studying global patterns in biodiversity. A survey of species richness and geographical range size did not show the decrease in range size from temperate regions to the tropics that had been previously assumed; although that pattern was largely true in the northern hemisphere, it did not appear to apply in the southern hemisphere. Research evaluating the relationship between extinction and human impact showed that, after controlling for species richness, the best predictors of the global pattern of extinction risk are measures of human impact, with ecological factors being of secondary importance. An examination of the distribution of rare