The rock ptarmigan (Lagopus muta) is a medium-sized game bird in the grouse family. It is known simply as the ptarmigan in the UK. It is the official bird for the Canadian territory of Nunavut, where it is known as the aqiggiq (ᐊᕿᒡᒋᖅ), and the official game bird for the province of Newfoundland and Labrador. In Japan, it is known as the raichō (雷鳥), which means "thunder bird". It is the official bird of Gifu, Nagano, and Toyama Prefectures and is a protected species nationwide. Unlike many arctic bird species, ptarmigan do not gain substantial mass to hibernate over winter. Etymology The ptarmigan's genus name, Lagopus, is derived from Ancient Greek lagos (λαγώς lagṓs), meaning "hare", + pous (πούς poús), "foot", in reference to the bird's feathered legs. The species name, muta, comes from New Latin and means "mute", referring to the simple croaking song of the male. It was for a long time misspelt mutus, in the erroneous belief that the ending of Lagopus denotes masculine gender. However, as the Ancient Greek term λαγώπους lagṓpous is of feminine gender, and the species name has to agree with that, the feminine muta is correct. The word ptarmigan comes from the Scottish Gaelic tàrmachan, meaning croaker. The silent initial p was added in 1684 by Robert Sibbald through the influence of Greek, especially pteron (πτερόν pterón), "wing", "feather", or "pinion". Description The rock ptarmigan is long with an tail and with a wingspan of and a weight of . It is smaller than the willow ptarmigan by about ten percent. The rock ptarmigan is seasonally camouflaged; its feathers moult from white in winter to brown in spring or summer. The breeding male has greyish upper parts with white wings and under parts. In winter, its plumage becomes completely white except for the black outer tail feathers and eye line. It can be distinguished from the winter willow ptarmigan by habitat and markings—the rock ptarmigan prefers higher elevations and more barren habitat. It also has a slender bill and a black eye stripe, which is absent in the willow ptarmigan. Sounds and displays Male rock ptarmigans emit a repertoire of guttural snores and rattles, most often directed to other males during breeding season. On open leks, single or multiple males also carry out displays on the ground and in the air to assert their territory, including chasing other males while flying. Aerial