Habitat utilization and breeding success in Leach's Storm-Petrel: the importance of sociality

Abstract

Models like "ideal-free distribution" that have been developed to predict the spatial distribution of animal populations typically assume that high densities will occur in preferred habitats. We investigated habitat utilization in Leach's Storm-Petrels (Oceanodroma leucorhoa) at the centre of the species' breeding range in the North Atlantic by comparing microhabitat features and breeding success in forest and open meadows on Great Island, Newfoundland. Leach's Storm-Petrels utilized forest more than open habitat. Overall, forest provided consistently better breeding habitat, with burrow density and activity and occupancy rates higher than in open habitat. A strong positive relationship between occupancy and both hatching and breeding success suggests that sociality plays an important role in habitat utilization and reproduction in Leach's Storm-Petrel.