DETERMINING THE AGE OF YOUNG BLUE GROUSE

A technique is described for determining the age of young blue grouse (Dendragapus ob- scurus fuliginosus) on Vancouver Island, based on the molt and development of juvenal and postjuve- nal primary feathers. When the method was tested on 73 wild birds whose approximate ages were known, 69 determinations (95 percent) were within 5 days of expected ages.