Long-term change in territory occupancy pattern of goshawks (Accipiter gentilis)

Abstract

:We examined territory occupancy (n = 161; 720 breeding attempts) of northern goshawks (Accipiter gentilis) in western Finland in 1983–1996. Nest sites of goshawks were characterized by old forests. The proportion of longstanding goshawk territories declined steeply from the beginning of the 1990s, while occasionally occupied goshawk territories became common. We suggest that the longstanding occupancy of the same territory, typical for goshawks, has decreased at least partly because of the logging of mature forests, which are preferred nesting habitats of goshawks. The mean occupancy rate of all goshawk territories, however, did not change through the study period, which suggests that the size of the breeding population has been constant.