Seasonal changes in spatial patterns and behavior of yearling male blue grouse on the breeding range

Changes in spatial patterns and behavior of yearling male blue grouse (Dendragapus obscurus) equipped with radio transmitters were recorded during spring and summer, 1980 and 1981, on Hardwicke Island, British Columbia. Sizes of home ranges decreased and yearlings appeared to become less dispersed as the season progressed. Most birds moved off their initial home range and onto new areas on the breeding range by late summer although the timing of this movement varied among individuals. Interactions involving yearling males with females and territorial males decreased as the season advanced. Changes in spatial patterns and behavior appear to be related to seasonal changes in levels of hormones in yearling males.