Females are nearly invisible against the tundra in summer, and are slightly smaller than males. All ptarmigans have feathered feet, which act as snowshoes, allowing the birds to walk in soft snow. The feathers may also increase insulation for these year-round arctic dwellers. Major summer diet is a mixture of plant material, especially blueberries, horsetail tips, crowberries, mountain avens, and heads of sedges. Winter foods are mostly buds and catkins of dwarf birch, and some willow buds and twigs.
Nesting habitat is most often a bare rocky outcrop with little vegetation.
Because some overhead protection is usually sought, the nest is often located close to a large rock. The female incubates 7 to 10 eggs without help from the male. Incubation typically lasts 21 days, and the downy chicks are able to leave the nest within a day of hatching. The female tends her young, but they feed themselves, and are able to fly at about 10 days. Chicks are independent at 10 to 12 weeks old.