The Nebraska Game and Parks Commission (NGPC) has monitored greater prairie-chicken (Tympanuchus cupido pinnatus) and plains sharp-tailed grouse populations (Tympanuchus phasianellus jamesi), collectively known as prairie grouse, since the 1950s using spring breeding ground counts and wing-ratio data collected from harvested birds in the fall. These indices have been used to evaluate population trends, but may be able to provide insight into the processes that drive patterns in the counts if related in space and time to environmental factors. An understanding of the processes shaping populations is of particular importance to prairie grouse because both greater prairie-chickens and sharp-tailed grouse are of conservation concern in portions of their respective ranges.