Rock Ptarmigan Life History

Habitat

Habitat Tundra

Rock Ptarmigan nest in arctic and alpine tundra, especially higher and drier parts of tundra with abundant lichen, mosses, and rocks (hence this species’ name). Such places have sparse vegetation, with dwarf willow, dwarf birch, and many small flowering plants such as mountain avens, arctic white heather, purple saxifrage, crowberry, blueberry, and bearberry. Willow Ptarmigan often nest and forage close by, but usually in lower, wetter areas with taller vegetation. Records of this species south of its overall breeding range, however, are very few, unlike for Willow Ptarmigan. Where these species overlap in range during winter, Rock Ptarmigan usually inhabits more barren habitats, above treeline, or large gaps in the boreal forest.

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Food

Food Plants

Rock Ptarmigan eat mostly plant buds, catkins, leaves, flowers, small twigs, berries, and seeds. They also consume spiders, insects, and occasionally snails, taken from the ground, from snow, and from low vegetation. They forage by walking slowly and browsing foliage with the sharp bill. Foods include arctic willow, dwarf birch, tufted saxifrage, purple saxifrage, nodding saxifrage, arctic poppy, sulphur buttercup, knotweed, longstalk starwort, bistort, flattop draba, mountain avens, bilberry, blueberry, bearberry, crowberry, lingonberry, horsetail, and seeds of various grasses and sedges.

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Nesting

Nest Placement

Nest Ground

Male and female both make shallow scrapes in barren, often very exposed spots in dry, stony tundra, sometimes in natural depressions next to rocks. The female selects the nest scrape, usually one of her own.

Nest Description

The female selects a flat area or natural depression in the tundra and deepens and shapes it with her feet, 0.4–2 inches deep. She lines the scrape with her own feathers, moss, lichens, and grasses from the immediate surroundings.

Nesting Facts

Clutch Size:3-13 eggs
Egg Description:

Pale buff with brown spots.

Condition at Hatching:

Completely covered with dense down, eyes open. Leave nest 6–12 hours after the last egg hatches.

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Behavior

Behavior Ground Forager

Rock Ptarmigan are highly territorial in spring, but conflicts between neighboring territorial males are usually resolved with threat displays rather than actual combat. At territorial boundaries, rivals square off and walk or run parallel to each, very near, stretching the neck, fanning the tail, and displaying the fleshy red combs above the eye while uttering gruff, barking calls. Territories vary greatly in extent, from about 10 acres to more than 100 acres. Males also perform spectacular flight song displays, in which they fly high into the air (as high as 260 feet), then begin a gliding descent with tail fanned and keeled upward, wings bowed downward, and eye-combs extended, all the while giving a staccato song. On landing, the male struts, fans the tail, drops the wings, and continues singing. Once males have mostly settled territorial boundaries, females walk through territories to inspect males, usually selecting a mate and his territory within a few days. To entice a nearby female, males perform elaborate courtship displays that involve erecting the eye-combs, fanning the tail, spreading or dragging the wings, wagging the head, bowing, circling the female, and calling. Females seldom switch mates after settling on territory with a mate, but many males (up to a third in some studies) are polygynous, having two female partners on their territory. Unlike with Willow Ptarmigan, females tend not to be aggressive toward other females. Monogamous pairs stay close to each other during courtship, and the male guards the females during incubation. When males are chasing off intruders, other males sometimes slip into the territory to mate with the female, without courtship and apparently against her will. Only females incubate the eggs. Just before the eggs hatch, males abandon the territories and gather into small flocks. Females tend young birds and sometimes gather into flocks that include multiple family groups (called crèches). After the young fledge and the adults’ molt is complete, Rock Ptarmigan in the northern parts of the range gather into flocks for migration. In some places, birds divide up according to age and sex. Large flocks (up to hundreds of birds) may fly very high during migration, sometimes over large expanses of water and sometimes in darkness. In the nonbreeding season males are not territorial. In spring, males are the first to return to the northerly breeding outposts, followed by females several weeks later.

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Conservation

Conservation Low Concern

Rock Ptarmigan are common and widespread in their far northern range. Partners in Flight estimates a global breeding population of 8 million and rates the species an 8 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Hunters around the globe take more than 1 million per year, but there have been no sustained studies of the impacts of hunting on populations. Habitat loss and changes resulting from changing climate likely represent the most profound conservation challenges for this species.

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Credits

Montgomerie, Robert and K. Holder. (2008). Rock Ptarmigan (Lagopus muta), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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