Habitat imprinting in breeding territory selection of a long-lived bird of prey.

Habitat imprinting is the phenomenon where exposure to cues in the natal habitat increases the probability of choosing a habitat with similar cues later in life. It is considered a key behavioural mechanism that decreases the costs associated with habitat selection. The similarity of breeding to natal habitats can be especially beneficial when choosing the first breeding site and when the choice has long-term consequences due to high site fidelity. Habitat imprinting in breeding habitat selection has rarely been documented in wild animals living in unmanipulated environments and is challenging to study in long-lived species with delayed maturity. We used a combination of genetic and visual identification to identify 354 white-tailed eagles Haliaeetus albicilla hatched between 1991 and 2015 that were subsequently documented breeding between 2001 and 2023 along the Baltic Sea coast or in the inland environments. We examined (a) the similarity of natal and breeding habitats and (b) the effects of natal dispersal distance on this similarity. Furthermore, (c) we were interested in breeding habitat selection and tested whether eagles showed a preference for natal-like habitats among suitable territories that were at the time still unoccupied. We found that breeding habitats were similar to natal habitats, independent of natal dispersal distance. Eagles were also more likely to choose a natal-like breeding site among available alternative sites. These results indicate that habitat imprinting is a possible driving mechanism in the habitat selection of long-lived animals with delayed maturity and has important implications for conservation actions such as eagle reintroduction programmes.