Griffon Vultures scavenging at night: trophic niche expansion to reduce intraspecific competition?

Abstract

Vultures feed exclusively on carrion and so are the only obligate scavengers among extant vertebrates (Ruxton and Houston 2004). Because the occurrence of carrion is unpredictable, vultures soar over large areas during daylight searching for carrion with their keen eyesight (Ruxton and Houston 2004). Although some data exist on vultures departing or arriving at roosts at dusk or dawn, respectively (Nathan et al. 2012), foraging outside daylight hours has only been reported in American Black Vultures (Coragyps atratus; Charette et al. 2011). We document here a new foraging behavior of Griffon Vultures Gyps fulvus, scavenging at night (Fig. 1), which has not been described in Old World vultures and adds to the repertory of unexpected behaviors reported for the species.