Spruce Grouse

Appearance

Spruce grouse are 38–43 cm long; males weigh 550–650 g and females 450–550 g. Races vary slightly in plumage, especially in the tail pattern and in the extent of white on the underparts, but in general adult males are mainly grey above and black below, with white spots along the side, and a red patch of bare skin over the eye. Adult females are mottled brown or mottled grey with dark and white bars on the underparts. Juveniles resemble females. Females may be confused with ruffed grouse but they have a dark tail with a pale band at the end and they do not erect their crown feathers when alarmed the way ruffed grouse do.

Distribution

As a specialist of the taiga, the spruce grouse is found throughout Canada. In the United States, it is present in Alaska, northern New England, northern Michigan, northeastern Minnesota, and the montane coniferous forests of Montana, Idaho, and Washington.

Spruce grouse are always associated with conifer-dominated forests, be they pine, spruce, or fir. They seem to prefer young successional stands. In summer they can be found near rich understory of blueberries and other shrub, and in winter they prefer denser stands.

Habitat

As a specialist of the taiga, the spruce grouse is found throughout Canada. In the United States, it is present in Alaska, northern New England, northern Michigan, northeastern Minnesota, and the montane coniferous forests of Montana, Idaho, and Washington.

Spruce grouse are always associated with conifer-dominated forests, be they pine, spruce, or fir. They seem to prefer young successional stands. In summer they can be found near rich understory of blueberries and other shrub, and in winter they prefer denser stands.

Reproduction

Males are promiscuous; they disperse and advertise a territory that is visited by females for mating. Females are solely responsible for the rest of the reproductive effort though males have been known to stay with young chicks and seem to aid in keeping the brood together. For a nest, they scratch a depression in the ground in a bush or under a low-lying coniferous branch or fallen tree, away from other females and from the males' territories. The nest is lined with grasses, leaves, and a few feathers. Nesting season is from early May to early July. Up to 10 eggs may be laid, the usual number being 4-7. Laying rate is 1 egg every 1.4 days. Eggs are about 40 mm in length and are tawny olive or buff, marked with blotches of brown. Incubation begins with the last egg laid and lasts about 24 days. Young are about 15 g at hatching and they are precocial; they walk out of the nest as soon as they are dry. They are capable of fluttering up from the ground at 1 week of age. The brood stays together and is accompanied by the hen, who broods them all night and frequently during the day until the young are 3–5 weeks old. Brooding behaviour of the female seems to be initiated by specific calls from the chicks when they are cold. At 70–100 days of age, chicks tend to leave the group and become independent.
Females breed only once a year. Most females first breed at 1 year of age, but about half the males delay establishing a territory until 2 years. The species' lifespan appears to be about 5–6 years in the wild, though one study in Southwestern Alberta has found two males and one female that lived to be at least 13 years old.

Food

The staple food is conifer needles, clipped directly from the tree, preferably the midcrown of pines though other conifers are exploited as well. In summer the birds can also forage on the ground, eating berries, green plants, fungi, and some insects. In winter, when only needles are consumed, the caeca increase in size to support digestion. The crop is also well developed: up to 45 cc of needles can be stored in the crop at the end of the day, to be digested over the duration of the night fast. Like other birds, spruce grouse consume grit or small stones to help their gizzard break down food. Chicks under 1-week old feed on insects and other arthropods, then switch to berries and fungi until the fall, when they start feeding on needles.

Predators

Spruce grouse eggs are taken by red squirrels, foxes, weasels, and probably corvids. Adults can fall prey to various hawks and owls, foxes, pine martens, and coyotes.