Some Comparisons of the Black-tailed and White-tailed Prairie Dogs in North-Central Colorado

Abstract

Black-tailed and white-tailed prairie dogs in north- auditory communications. The species differed markedly in the type, number, and construction me.thods of the burrow entrances. The black- tailed prairie. dogs altered their above-ground environment behaviorally, but the white-tailed did not. Both were diurnal, with two periods of maximum surface activity durin, the summer. Black-tailed prairie dogs generally confined their daily activities to definite boundaries; the white- tailed did not. Pups of both species spent considerable time in play. Pups of the black-tailed species displayed much care-soliciting behavior directed at the adults; pups of the white-tailed species did not. Black- tailed prairie dogs remained active above ground throughout the year, but with less total activity during winter than summer. White-tailed prairie dogs completely terminated surface activity during winter; adult males were the first to appear above ground in early spring and the first to become inactive in early summer; adult females appeared a little later and remained active slightly longer; pups remained active above ground until fall. Food habits varied with the time of year and the availability of vegetation. The black-tailed species ate mostly forbs and grasses, the white-tailed mostly grasses and sedges. The black-tailed prairie dogs consumed many roots; the white-tailed never ate roots. The density of burrow entrances and animals was greater for the black- tailed than for the white-tailed prairie dogs. The black-tailed species bred during late February; births occurred in late March and April, and the pups appeared above ground in early May. The white-tailed species bred in late March; births occurred in early May, and the pups appeared above ground in early June. There was no evidence to indi- cate yearlings were less successful breeders than adults with either spe- cies. There appeared to be no mortality between the time of conception and the initial appearance of the pups above ground for the black-tailed species, but almost 40% of the embryos were lost in this interval with the white-tailed species. Immigration and emigration played little part in the dynamics of the black-tailed species, but were more important for the white-tailed species. Badgers were the principal predators for both species and drowning contributed to mortality at both study sites. The black-tailed prairie dogs were longer than the white-tailed species, mostly because their tails were longer. Females of both species were similar in weight, but male white-tailed prairie dogs were heavier than the black-tailed of either sex.