Response of Raptors to Reduction of a Gunnison's Prairie Dog Population by Plague

Abstract

-Raptors were counted at approximately 2-week intervals between March and November 1985-1987 in the Moreno Valley, Colfax Co., New Mexico. During that period, an epizootic of plague (Yersinia pestis) swept through the valley and sequentially killed Gunnison's prairie dogs (Cynomys gunnisoni) n three areas of approximately 25 km2 each. Red-tailed hawk (Buteo jamaicensis) numbers did not change significantly over the study period. Although golden eagles (Aquila chrysaetos) declined in abundance, their numbers did not recover with the recovery of prairie dogs in 1987. Ferruginous hawks (B. regalis) were abundant during autumn migration where prairie dogs were abundant, but their numbers declined significantly with the population decline of prairie dogs. Gunnison's prairie dogs appeared to be an important food resource for ferruginous hawks during their migration through the Moreno Valley.