Studies of territoriality among male spruce grouse (Canachites canadensis) were conducted on the Kenai Peninsula, southcentral Alaska; from 1965 tol967. Data on movements and behavior were obtained during the breeding season by instrumenting 13 males with radio transmitters. During late April and the first 3 weeks of May, all adult males were localized on parcels of forest 5 to 9 acres in size, where drumming and courtship displays occurred. The defensive behavior exhibited by males on these sites suggested that they could be termed territories. Some juvenile males (presumed to be territorial) were localized on areas 3 to 21 acres in extent during the breeding season, but other juveniles were not localized and wandered extensively about an activity center, often ranging out a distance of a mile from the activity center within a 24-hour period. During these excursions, the wandering juveniles were often found drumming with localized juvenile or adult males. Presumed activity centers of juvenile males ranged in size from 6 to 16 acres, To assess density of males in spring, a census was conducted on a 2-squaremile plot during the period males were localized in late April and May. The number of wandering juveniles with activity centers on the plot was difficult to enumerate, and probably resulted in some error. Censusing of the plot suggested a density of approximately ten males per square mile in1965 and 1966, and 7 per square mile in 1967. In the latter two years, the spring population was composed of about 30 percent territorial adults and 70 percent juveniles, with one-half or fewer of the juveniles being territorial.
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