The Specific Distinctness of the Greater and Lesser Prairie Chickens

Abstract

SOME disagreement exists as to whether the Lesser Prairie Chicken (Tympanuchus pallidicinctus) and the Greater Prairie Chicken (Tympanuchus cupido) are distinct species or members of the same polytypic species. Aldrich and Duvall (1955: 8) have considered these birds to be conspecific, although without argument other than the statement: . . we find no characters that differ from those of the other prairie chickens, except in degree; thus, only a racial difference is indicated. The A.O.U. Check-list of North American birds (1957), however, continues to agree with Peters (1934: 41), Ridgway and Friedmann (1946: 219), and earlier workers, and lists them as separate species. The essentials of the past and present distributions of the prairie chickens are shown by Baker (1953: 5) and by Aldrich and Duvall (1955: 8-9). The Greater Prairie Chicken occupies, or has occupied, a wide, gradually changing, partially disjunct range in the eastern and central United States and is undramatically polytypic. Of the races T. c. pinnatus, attwateri, and cupido, the last (or Heath Hen of the north Atlantic coast) is extinct and attwateri is threatened with extinction (Auk, 80: 360, 1963). The Lesser Prairie Chicken occupies a comparatively small range to the southwest of the Greater, today occurring in eastern Colorado and New Mexico, western Kansas and Oklahoma, and northern Texas. It is monotypic. While the morphological characters that separate the Greater and Lesser prairie chickens may differ only in degree, the degree seems greater to my eye than that separating the several races of the Greater Prairie Chicken, especially with regard to coloration and markings. Since the study of behavior has already been used to throw light on the evolutionary trends in North American and European grouse, for example by Wing (1946), Scott (1950), and Hamerstrom and Hamerstrom (1960), the present study was undertaken with the hope that similarities and differences in courtship behavior, as well as in behavior through the remainder of the year, might help in assessing the validity of recognizing these two prairie chickens as distinct species. The data here presented have been obtained by observing the birds on the booming and feeding grounds, by flushing them from coverts, and by tracking them in the snow, sand, and mud.