Influence of changing grouse density and forest attributes on the occupancy of a series of potential territories by male ruffed grouse

Abstract

The history of occupancy of 117 territories established by male ruffed grouse (Bonasa umbellus) on a 700-ha study area in southwestern Alberta was studied over 11 years in relation to changing density of the grouse and attributes of the surrounding forest. The pattern of use of territories varied from continuous occupancy by a series of different birds over as many as 11 years to sporadic occupancy for as little as one season. These two extremes differed in that continuously occupied territories possessed numerous acceptable display sites, were located towards the center of clumps of territories, and hosted long-lived birds. By contrast, sporadically occupied territories possessed few acceptable display sites, tended to be located at the periphery of clumped territories, and hosted short-lived birds. Although the status of the vegetation around the display sites within the territory was a major factor influencing its occupancy, social interactions among the grouse also appeared to influence the history of its use.