Breeding and movements of goshawks in boreal forests in Sweden

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Abstract
Goshawks were studied in their boreal forest breeding habitat in central Sweden from 1977 to 1982. Nests were regularly spaced, with a nearest neighbour distance of 6.3 km. corresponding to a density of about 3 pairs 100 km−2. Of initiated breedings. 68% were successful. There was no difference in breeding performance between years. Average brood size was 2.7. Sex ratio among first captures of adults was even, but males were recaptured more often than females. Nearly all juveniles left the area in winter. Among radio‐tagged adults 20% of the males, and 50% of the females moved out of the area. When moving, both adults and juveniles moved into agricultural areas, the juveniles generally covering longer distances. From autumn to spring, body condition of females improved, whereas that of the males deteriorated. It is argued that the males' stronger tendency to stay in winter is due to the advantage of possessing a territory in early spring. Females, on the other hand, can move to areas with as good food conditions as possible.