Lek Numbers as a Trend Index to Prairie Grouse Populations

Abstract

Traditionally, annual population indices of prairie grouse (Tympanuchus spp. and Pedioecetes phasianellus) are based upon counts of males displaying in spring at leks. It is assumed that the number of displaying males is directly proportional to population size (Lehmann 1941, Schwartz 1945, Grange 1948, Hart et al. 1950). Two reconnaissance techniques currently are used to monitor trends in numbers of displaying males: average size (number of displaying males/lek) of selected leks (J. Herd, unpubl. rep., Oklahoma Fed. Aid Proj. W-82-R-15, 1976; Byard 1979) and total number of leks/area (J. Horak, Kansas Fish and Game Commission, and R. DeArment, Texas Parks and Wildlife Department, pers. commun.). The former has been questioned as an indicator (Kirsch et al. 1973), and the latter was proposed recently by Sisson (1976). We evaluated these 2 techniques with data from 4 long-term studies of prairie chickens.