Diet Diversity and Dietary Overlap of Two Sympatric Vulture Species in Hirpora Wildlife Sanctuary, Kashmir

Abstract

Bird species that use similar resources are expected to use variant foraging approaches and segregate in order to minimize a possible competition among them. However, if they fail to attain this exclusion, competition results. We studied the diet composition and dietary overlap between two sympatric vulture species: Himalayan vulture (Gyps himalayensis) and Bearded vulture (Gypaetus barbatus), the two important avian scavengers of Hirpora Wildlife Sanctuary of Kashmir Himalaya. Analysis of pellets collected from feeding and roosting sites of these vulture species revealed a significant variation in their food consumption with Himalayan species consuming mostly larger dead mammalian species with higher frequency occurrence of 66.66% of Bubalus bubalus and bearded species the smaller dead mammalian ones with highest frequency occurrence of Ovis aries (83.82%). Diet spectrum of Himalayan vulture was more diverse (H’=1.97) than that of Bearded vulture (H’=1.64). The values of Berger-Parker index (Pimax) follows the reverse order of diversity with Pimax=36.2% for Himalayan vulture and Pimax =48.7% for Bearded vulture. There was very low dietary overlap between the two species (Ojk=0.466; C=0.457) which may favor their co-existence. The management of carrions of livestock and setting up of vulture restaurants is the need of the hour for the conservation of these scavenging birds which are facing high risk of extinction in Hirpora Wildlife Sanctuary.