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Sooty Grouse Life History

Habitat

Habitat Forests

Sooty Grouse inhabit coniferous forests in mostly mountainous areas (up almost to treeline), although they breed in forests at sea level in the northern part of the range. Most breeding habitats are open forests, and both old-growth forest with gaps as well as regenerating logged or burned areas attract Sooty Grouse, so long as there are plenty of grasses and shrubs. They tend not to use closed forests, high alpine, or shrubsteppe habitats. Key tree species include lodgepole pine, limber pine, mountain hemlock, western hemlock, Douglas-fir, subalpine fir, white fir, Engelmann spruce, Sitka spruce, and western redcedar, along with other pine species.

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Food

Food Plants

In winter, Sooty Grouse eat the needles of conifers (especially Douglas-fir, firs, and hemlocks), along with buds and twigs, which they pluck and prune with their strong bills, usually while perched in the middle or upper part of the tree. They tend to forage in the early morning and late afternoon. When males display, they perch in trees and they mostly feed in these same trees. As spring approaches, Sooty Grouse begin to eat more insects along with leaves, flowers, and berries. Plant foods include wolfsbane, cat’s ear, buckwheat, horseweed, and salal berries, along with larch, willow, cherry, balsamroot, hawthorn, currant, serviceberry, buffaloberry, strawberry, blackberry, raspberry, rose, bearberry, huckleberry, vetch, clover, and fern. Young birds eat insect prey, including ants, beetles, grasshoppers, and spittle bugs, sometimes gleaned from vegetation but most often pecked from the ground. Like other grouse, Sooty Grouse eat grit or tiny stones, which they often collect along road edges, to help grind up food in the gizzard. Females often bring young into open environments, especially where grasshoppers and seeds are plentiful.

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Nesting

Nest Placement

Nest Ground

Females build ground nests, usually well away from males’ spring territories and usually away from other females’ nests. Most nests have overhead cover, such as shrubbery, but some are in exposed areas.

Nest Description

Females make a shallow scrape about 6.7 inches across and 1.8 inches deep. They line the scrape with materials close by: leaves, twigs, needles, moss, bark, and a few feathers.

Nesting Facts

Egg Description:

Pale buff, speckled with brown

Condition at Hatching:

Downy and able to follow mother.

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Behavior

Behavior Ground Forager

During the breeding season, male Sooty Grouse display from trees to attract females; the closely related Dusky Grouse displays mostly from the ground. Male Sooties perform short fluttering flights out from a tree, with much wing noise, and give up to 6 very low-pitched, loud hoots that carry fairly far through the forest. These display perches (known as “songposts”) can be more than 100 feet high in a tree. Males do not gather on communal display areas (“leks”) but do sometimes call in response to other calling males. Females attracted by these displays often reveal themselves with a soft cackle, which causes the male to descend from the songpost to the ground. There he puffs up his plumage, fans the tail, droops the wings, bobs the head, and struts around the female, calling and exposing yellowish sacs at the side of the neck. Males are probably polygynous, meaning they mate with more than one female. It’s not known whether females also have multiple mates. Males use threat postures, growling calls, and chase flights when confronting rivals that venture too close to their display area, and they sometimes engage in physical combat. After mating, males are sometimes aggressive toward females, occasionally attacking them. Females may also chase and peck other females. After courtship and mating, males have no more involvement with the female or young. Females select the nest site, construct the nest, incubate the eggs, and raise the young to fledging. After the young have grown to adult size, some disperse, but others may remain with the female. In winter, small groups (probably families) often forage and roost in a set of trees for several weeks before moving on.

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Conservation

Conservation Declining

According to the North American Breeding Bird Survey, Sooty Grouse populations declined by about 1.8% per year between 1968 and 2015, resulting in a cumulative loss of 57% over that period. Partners in Flight estimates a global breeding population of 2 million and rates the species a 13 out of 20 on the Continental Concern Scale, indicating a species of low conservation concern. Nevertheless, if current rates of decline continue, the species will have lost another half of its population by 2088. The reasons for the apparently rapid decline of Sooty Grouse are still largely unknown. Although they still occupy much of their former range, Sooty Grouse have disappeared in places where development has cleared forest for housing or agriculture, such as in western Washington. Some types of logging may be briefly beneficial for the species.

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Credits

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

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

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

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