White-tailed ptarmigan

thumb|A white-tailed ptarmigan in fully-white winter plumage.

thumb|A ptarmigan displaying its natural camouflage, matching the patterns of the lichen covered rock of its environment.

The white-tailed ptarmigan (Lagopus leucura), also known as the snow quail, is the smallest bird in the grouse tribe. It is a permanent resident of high altitudes on or above the tree line and is native to Alaska and the mountainous parts of Canada and the western United States. Its plumage is cryptic and varies at different times of the year. In the summer it is speckled in gray, brown and white whereas in winter it is wholly white. At all times of year the wings, belly and tail are white. The white-tailed ptarmigan has a diet of buds, leaves, flowers and seeds. The nest is a simple depression in the ground in which up to eight eggs are laid. After hatching, the chicks soon leave the nest. At first they eat insects but later move on to an adult diet, their mother using vocalisations to help them find suitable plant food. The population seems to be stable and the IUCN lists this species as being of Least Concern.

Taxonomy and etymology

The white-tailed ptarmigan was given the scientific name Tetrao (Lagopus) leucurus by the Arctic explorer John Richardson in 1831. It was later determined that Lagopus had sufficient distinguishing features to be regarded as a separate genus and the bird became Lagopus leucurus. Molecular studies have shown that Lagopus is monophyletic, with the rock ptarmigan (Lagopus muta) and White-tailed ptarmigan being sister species. The position of the willow ptarmigan (Lagopus lagopus) is less clear cut, it showing some genetic divergence over its wide range.

The genus name Lagopus is derived from Ancient Greek lagos (λαγως), meaning "hare", + pous (πους), "foot", in reference to the bird's feathered legs. The species name leucura was for a long time misspelt leucurus, in the erroneous belief that the ending of Lagopus denotes masculine gender. However, as the Ancient Greek term λαγωπους is of feminine gender, and the species name has to agree with that, the feminine leucura is correct. The species name leucura is derived from the Latinized version of the Greek leukos, meaning "white" and oura, meaning "tail", in reference to the bird's permanently white tail.

The white-tailed ptarmigan has five recognized subspecies:

L. l. altipetens (Osgood, 1901)
L. l. leucura (Richardson, 1831)
L. l. peninsularis (Chapman, 1902)
L. l. rainierensis (Taylor W, 1920)
L. l. saxatilis (Cowan, 1939)

Description

The white-tailed ptarmigan is the smallest of the ptarmigans and the smallest bird in the grouse tribe. It is a stocky bird with rounded wings, square-ended tail, small black beak and short legs with feathering extending to the toes. Adults are long, with the males being only slightly larger than the females. The average weight is . During the summer, the white-tailed ptarmigan is a speckled grayish brown with white underparts, tail and wings. In the fall, the plumage has turned a much more reddish-brown color and white feathers begin to grow through. By winter all the summer brown feathers are lost and the bird is completely white. A further molt in the spring precedes the breeding season and the bird returns to its summer plumage. The finely barred greyish coloration on the back makes it easy to distinguish this species from the much browner willow ptarmigan and rock ptarmigan. Both sexes maintain white tail and wing feathers all the year and males can be identified by their reddish eyecombs (fleshy growths above the eye), also present year-long. In general this bird is silent but it sometimes makes quiet, low-pitched hoots and soft clucking noises.

Distribution

The white-tailed ptarmigan is an alpine species, a permanent resident of the high mountains above or near the timber line. It occupies open country and flies a great deal more than forest grouse, but still prefers running to flying. It ranges from Alaska and western Canada south to northern New Mexico. Males return from their wintering areas to establish territories on spruce-willow timber line breeding grounds in April. Females arrive in early May and pairs are formed.

The white-tailed ptarmigan is the only bird in North America to reside permanently in the alpine zone.

The white-tailed ptarmigan was first introduced into Oregon's Wallowa Mountains with 36 birds taken from Colorado and Washington in September 1967. A second set of 54 birds was released in September 1968 that were supplied from Colorado and British Columbia. Although a few of the birds were observed in the spring and summer of 1969 the effort to establish a population in Oregon was ultimately unsuccessful.

thumb|An individual with late summer plumage blends into subalpine tundra

thumb|Full summer plumage

Diet

This herbivorous bird's diet varies seasonally. Nitrogen-rich snow buttercup leaves are favored in the spring season, while willow catkins, mountain avens flowers, and chickweed blooms, other flowers and leaves, lichens and berries form the majority of the ptarmigan's diet in the summer. During the summer, the ptarmigan eats grit to assist in digesting plant material. One side of the nest generally provides a quick escape route. The young birds remain with their mother throughout the summer and autumn season.

The white-tailed ptarmigan has feathers located on its feet to serve as protection from the extreme cold often experienced in the alpine tundra environment. In addition, these birds have feathers around their nostrils to warm the air prior to entry into the respiratory tract. The most obvious adaptation is this bird's cryptic coloration, which enables it to blend in with its environment and avoid predation by golden eagles or other birds of prey.