Avian assemblages of black-tailed prairie dog (Cynomys ludovicianus) colonies were compared to those present at two types of non-colonized grassland, during the breeding season, in southwestern Kansas and southeastern Colorado. Relative abundances were quantified in 1996 during a period of drought and in 1997 during a period of above average precipitation. We detected fewer bird species at all sites in 1996 than in 1997, and the total number of bird species detected on prairie dog colonies was lower than that detected on both types of non-colonized areas during both years. Horned larks (Eremophila alpestris) had higher relative abundances on non-colonized sites in 1996, but were more abundant on prairie dog colonies in 1997. Lark buntings (Calamospiza melanocorys) and grasshopper sparrows (Ammodramus savannarum) were not recorded at the study sites in 1996, but appeared in high numbers in 1997. These two species, and western meadowlarks (Sturnella neglecta), had higher relative abundances on non-colonized sites in 1997 than on prairie dog colonies. A comparison of our results with those of other studies suggest that the effects of prairie dogs on associated biota might not be identical in all regions of the Great Plains, or under all environmental conditions.