Forty wild-trapped white-tailed ptarmigan (Lagopus leucurus) were released onto Pike's Peak, Colorado, in June (six mated pairs) and September (9 males, 7 females, 12 juveniles) 1975. Numbers declined 37.5% by the first spring (1976) after the introduction. Spring densities gradually recovered, increasing from 3.4 grouse per 100 ha of breeding habitat in 1976 to 8.4 in 1979, then declined to 7.4 in 1980. Mean distance of territories from the release area increased only 0.86 km (p = 0.44) from 1976 to 1980, reflecting a slow process of expansion. Reproduction was documented in all years including 1975. Survival of released birds until 1976 was 93.3% for males, 46.1% for females, and 33.3% for juveniles. Time of release did not influence survival. Average annual survival (1976–1980) was 64.9% for adult males, 60.3% for adult females, and 43.1% for juveniles. Yearlings comprised 39.7% (range, 20.0 to 54.9%) of all birds (N = 219) identified exclusive of juveniles. Of the 219 birds identified, 137 (62.6%) were males.