Abstract/Summary

Nest-site selection by species is expected to be adaptive and lead to improved breeding productivity, but in some settings, there exist mismatches between preferred nesting habitat and breeding productivity. We tested the expectation that nest-site selection is adaptive in a sample of 63 nests of a long-lived social species that breeds and forages in groups: the critically endangered White-backed Vulture (Gyps africanus). By studying breeding groups in the same area, we controlled for landscape-level effects on habitat selection and investigated how fine-scale nest-site characteristics affect breeding productivity. We developed models to assess how nine characteristics of nest-sites selected by breeding vultures compared with 70 random trees, and tested associations between these characteristics and breeding productivity. WbVs selected nest-sites in taller trees (> 7m), but neither tree height nor any other nest-site characteristics had a clear effect on breeding productivity. Vultures selected nest trees closer to each other than random trees, and the associations between nest density, nearest neighbour distance and breeding success were all positive. These positive associations and the absence of an observable effect between nest-site characteristics and breeding productivity suggest that for this semi-colonial breeder, the social imperative of proximity to conspecifics (i.e. nesting near other vultures and group foraging) may be more important than individual nest-site selection.