Analysis of the Drums of Ruffed Grouse

Abstract

MANY bird studies have shown individual differences in vocalizations within one species. For the most part such spectrographic studies deal with passefine songs, but some work with game birds has been done. Beightol and Samuel (1973) recently completed an analysis of American Woodcock (Philohela minor) vocalizations and showed that individual birds were readily identified by their voice prints. Williams (1971) also found individuality in calls of Bobwhite (Colinus virginianus). If identi-fication of the drums of individual Ruffed Grouse (Bonasa umbellus) were possible then it could be used as a new "tool" for study of longevity and movements of this bird. The drum of the Ruffed Grouse is a nonvocal sound produced by rapid wing strokes (for an exact description of this display, see Hjorth 1970: 225-232). Aubin (1972) examined this nonvocal form of com-munication and concluded that Ruffed Grouse "answer drumming sounds" of nearby birds, and that the number of wing strokes and the duration of each drum were variable for an individual bird.