Systematic List of Old World Vultures: The Griffons

This chapter examines the forms, foraging and feeding habits, breeding patterns and statuses of the eight species of Griffon vultures of the Genus Gyps (Savigny 1809). The Gyps vultures are a genus of Old World vultures in the family Accipitridae, which also includes eagles, kites, buzzards and hawks. Compared to other vultures, the heads of Gyps species are more feathered, with a characteristic downy cover.

The eight Gyps species are: the White-backed vulture (Gyps africanus); White-rumped vulture (Gyps bengalensis); Cape Griffon (Gyps coprotheres); Griffon vulture (Gyps fulvus); Himalayan vulture (Gyps himalayensis); Indian vulture (Gyps indicus)— formerly Long-billed vulture; Ruppell's vulture (Gyps rueppellii); and Slender-billed vulture (Gyps tenuirostris)—formerly included in G. indicus. A prehistoric species, Gyps melitensis is known only from fossil remains found in Middle to Late Pleistocene sites all over the central and eastern Mediterranean.

Gyps species are unique among Old World vultures in that they feed exclusively as scavengers, whereas other vultures are also known to kill their prey on occasions or, rarely, to feed on fruits (i.e., the Palm-nut vulture Gypohierax angolensis (Houston 1983; Mundy et al. 1992; del Hoyo et al. 1994; Johnson et al. 2006). Specialization in feeding behavior among Gyps vultures is thought to have evolved due to their close association with ungulate populations, particularly migratory herds in Africa and Asia. In fact, the observed temporal and geographic diversification of Gyps vultures coincides with the diversification of Old World ungulates, especially those of the family Bovidae (Vrba 1985; Arctander et al. 1999; Hassanin and Douzery 1999; Matthee and Davis 2001), and the expansion of grass-dominated ecosystems in Africa and Asia (Jacobs et al. 1999).

These close associations likely played a significant role in the adaptation and rapid diversification of Gyps vultures. Indeed, Houston (1983) proposed that their large body size and ability to soar over large distances in search for food are related to the associated migrant distributions and seasonal fluctuations in the mortality of ungulates, and that they have consequently become incapable of actually killing their own prey (Ruxton and Houston 2004).

The Indian vulture, Ruppell's Griffon vulture and the Common Griffon vulture have been argued to be polytypic or descended from several sources (Mayr and Cottrell 1979; Sibley and Monroe 1990; del Hoyo et al. 1994; Ferguson-Lees and Christie 2001). Wink and Sauer-Gurth (2000) found that G. rueppellii and G. himalayensis may be closely related in a monophyletic group with G. coprotheres and G. fulvus, based on nucleotide squences of the cytochrome b gene. Arshad et al. (2009a) supported this position and argued that there was a recent, rapid diversification among the Gyps vultures, possibly related with the diversification of wild ungulates in the Old World. G. bengalensis and G. africanus were formerly classified together as a separate species, Pseudogyps, as unlike other Gyps species they shared a smaller body size and a reduced number of rectrices (wing feathers, 12 vs. 14 for the other species) (Mundy et al. 1992; Sharpe 1873, 1874; Peters 1931).

In addition, proposals were made to consider the 'long-billed' vultures as two separate species (G. indicus and G. tenuirostris) based on morphological differences (Grey 1844; Hulme 1869, 1873; Rasmussen et al. 2001, 2005), and the taxonomic status of the two subspecies of the Eurasian vulture (G. f. fulvus and G. f. fulvescens), as well as their characteristics and geographic distribution are unclear. Currently, taxonomic relationships among Gyps species, including subspecies relationships, have yet to be fully studied with molecular sequence characters, and the validity of fulvescens has not been considered in recent times (Hulme 1869, 1873; Jerdon 1871).