Spacing and habitat use of capercaillie during summer

Abstract

We radio-tracked 52 capercaillie males and 21 broodless females during June, July, and August, 1979–1986, in a 100-km 2 coniferous forest in central Scandinavia. After display activity ceased in early June, 77% of adult males made distinct movements, averaging 1.5 km, from lek territories to summer ranges. A similar movement was made by 48% of the females after loss of nest or brood. Males were now nonterritorial, and lived solitarily in overlapping home ranges averaging 170 ha. In June and July, they used successional stages in proportion to availability, but in August they preferred old, natural forest. Females, having home ranges averaging 103 ha, commonly formed small social groups of two to four individuals. They preferred young plantations throughout summer, and also preferred denser habitats than males. Both sexes returned to the same summer ranges in consecutive years. Home ranges of both sexes were distributed in a clumped spacing pattern. This can be explained by preference for patchily distributed habitat types in males, and habitat preference and sociality in broodless females.