Guide to North American Birds

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Photo: Jukka Jantunen/Vireo

Rock Ptarmigan

Lagopus muta

A hardy grouse of barren ground in the high Arctic, well adapted to harsh surroundings. Well camouflaged by white winter plumage and mottled brown summer plumage; male molts later in spring than female, so early in the breeding season he remains conspicuously white while she becomes almost invisible against the tundra.

Conservation status	May become locally scarce near Arctic settlements, but still very common over vast areas of northern wilderness.
Family	Pheasants and Grouse
Habitat	Above timberline in mountains; bleak tundra of northern coasts. Summers on relatively dry, open tundra, with rock outcrops and arid ridges mixed with areas of dwarf willow and birch, sedge meadows. On islands (such as Aleutians), may occupy all open habitats. In winter, many remain in summer habitat, but some move into shrubby areas, openings in northern forest.

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Feeding Behavior

Forages while walking by picking rapidly at vegetation, nipping off food with bill. In winter, may sometimes follow herds of caribou or musk-ox, feeding where animals have scraped away the snow.

Eggs

4-13, usually 7-9. Pale buff with brown spots. Incubation is by female only, usually about 21 days; begins after laying next to last egg. Young: Downy chicks leave nest with adult female within a day after hatching. Female tends young, but young feed themselves. Capable of short flights at 7-10 days, can fly fairly well at 10-15 days. Young are independent at age of about 10-12 weeks.

Young

Downy chicks leave nest with adult female within a day after hatching. Female tends young, but young feed themselves. Capable of short flights at 7-10 days, can fly fairly well at 10-15 days. Young are independent at age of about 10-12 weeks.

Diet

Mostly buds, leaves, and seeds. Adults are almost entirely vegetarian, feeding on buds, catkins, leaves, flowers, berries, and seeds. Major food sources include willow, dwarf birch, alder, saxifrage, crowberry. Also eats some insects, spiders, snails; young chicks feed on these items heavily at first. Regularly swallows grit to help with digesting rough plant material.

Nesting

Male defends territory in spring with conspicuous display flight: flaps very rapidly, glides high, then flutters to ground while giving staccato call. In courtship display, male raises red combs above eyes, fans tail, and walks in circles around female, dragging one wing on ground. Nest site is on ground in relatively barren, rocky area, usually near large rock. Nest (built mostly by female) is shallow depression, lined with small amounts of moss, lichen, grass, feathers.

Illustration © David Allen Sibley.
Learn more about these drawings.

Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Leaves northernmost parts of breeding range and highest mountains in winter, moving to lower elevations and southward. A regular influx to some areas south of breeding range, but not extending much south of tundra regions. Migrates in flocks.