White-tailed ptarmigan listed as "Vulnerable". This bird serves as an indicator species for the alpine tundra, and denotes overall ecosystem health. It is not a conservation concern and is abundant in alpine zones across North America, indicating that this region is not undergoing dramatic climatic, temperature, or precipitation shifts. The lack of overgrazing by cattle, the lack of human development in alpine zones, the difficulty in accessing its remote habitat, the low densities at which it occurs and the laws regarding the limits to hunting bags allow the white-tailed ptarmigan to thrive. White-tailed ptarmigan The white-tailed ptarmigan ("Lagopus leucura"), also known as
Winter white dwarf hamster able to sense a directional change in photoperiod length, such as in one experiment that demonstrated a transition from 16 hours of light to 14 hours initiates a change to the winter coat. The change to the winter coat can be triggered in the summer by the short day lengths. The change occurs back to the summer coat in the autumn, when the length of the days change again. At internal temperatures hamsters in captivity start later with the changes. The winter colour is less pronounced in them. The eyes of the Winter white hamster are black, unless it is