From Wikipedia Picture of the Day; March 19, 2018:

The Rock Ptarmigan (Lagopus muta) is a medium-sized gamebird in the grouse family. Averaging 34–36 cm (13–14 in) long, with a wingspan of 54–60 cm (21–24 in), this species feeds primarily on birch and willow buds and catkins. The rock ptarmigan breeds across arctic and subarctic Eurasia and North America and commonly has up to six chicks. This Japanese rock ptarmigan (L. m. japonica), locally known as the raichō (雷鳥) which means “thunder bird”, in summer plumage on Mount Tsubakuro, Japan

Photo: Daiskue Tashiro