High occurrence of polygynous trios in a dense Egyptian Vulture Neophron percnopterus population

Field surveys and camera traps close to nest sites were used to study the nesting biology of a dense population of Egyptian Vultures Neophron percnopterus on Masirah Island, Oman. Camera-trap images from one nest revealed the laying of a third egg in a nest and incubation of the clutch by three individually identifiable adults (a male and two females). Another male and two females were photographed copulating in a different nest. Behavioural observations revealed the presence of five more probable polygynous trios and another trio with unknown sex composition. A surplus of adult non-breeders was recorded at the traditional main communal roost. The high occurrence of polygynous trios within a dense population, combined with an abundance of non-territorial Egyptian Vultures, may be explained by habitat saturation in a species exhibiting a tendency for natal dispersal that is inversely density dependent.