Breeders and floaters use different habitat cover: should habitat use be a social status-dependent strategy?

Abstract

In order to understand habitat requirements in territorial species, it is important to take into account the specific tasks and constraints associated with the different stages and social status of an individual life cycle (e.g. territorial breeder or nonterritorial floater). However, social status has rarely been taken into account in studies on habitat preference, selection and use. In the present study, we compare habitat characteristics near nesting sites of Eagle Owl Bubo bubo breeders with those of diurnal roosting places chosen by floating owls. As both nesting and roosting sites are important components of an individual’s fitness (e.g. mating success vs. survival), we expected that the use of those locations would reflect the different cost–benefit trade-offs related to the status of breeder and floater, respectively. By analysing the structure of the forest stands and the landscape features surrounding both places at two spatial scales, we found that: (1) breeders and the floaters used forest stands with a different vertical structure; compared with the floaters, the breeders used more mature stands characterised by higher trees; (2) as expected, breeders and floaters did not show any specific habitat use at the landscape scale. Our results showed a clear discrepancy in habitat use according to social classes, suggesting social tasks/constraints (successful reproduction vs. overcoming dispersal costs) as potential determinants of two divergent strategies in habitat use.