Early stages of home range settlement in a newly reintroduced raptor on an island: Bonelli’s eagle (Aquila fasciata) on Mallorca, Spain

Abstract

Bonelli’s eagle (Aquila fasciata) had become extirpated in parts of their Mediterranean distribution, such as on Mallorca Island (Balearic Islands, Spain). Thanks to reintroduction programs, a new breeding population was reintroduced to the island, between 2011 and 2017. To identify movement patterns within the island, we equipped each reintroduced individual with a GPS device before release to track their movements. Home range of reintroduced eagles were calculated using a KDE — kernel density estimation approach. Although we found that home range size differed for individuals among years and sex, we found a high degree of overlap in home range in the study population. The home range of each individual remained stable in size and shape and few explorative flights outside the delineated home range were observed. In conclusion, reintroduced Bonelli’s eagles have adapted to Mallorca Island by breeding earlier than already established populations, reducing their dispersive behaviour, and accelerating establishment of home ranges.