Colorado · UplandWhite-tailed ptarmigan

White-tailed ptarmigan occupies alpine tundra above treeline across Colorado's mountains, and the regulation's own two-season GMU split maps onto a real, independently-documented population structure. Genetic research on Colorado's population (cited via a CPW-hosted population-assessment item) identifies fine-scale structure between a "South" population in the San Juan Mountains and a "North" population spanning the central and northern mountain ranges, plus isolated smaller pockets in the Flat Tops and Sangre de Cristo ranges. The existing record's Season 2 area (GMUs 44, 45, 53, 54, 66, 67, 68, 70, 71, 74-81, 444, 751) corresponds closely to the San Juan Mountains, the South population, while Season 1 covers the rest of the state's alpine habitat, i.e., the North population plus the isolated pockets. Researchers describe adequate gene flow across the whole state to maintain genetic diversity, and no indication of severe small-population effects in the isolated pockets, despite the naturally fragmented nature of alpine habitat itself.