The spruce grouse or Canada grouse (Falcipennis canadensis) is a medium-sized grouse closely associated with the coniferous boreal forests or taiga of North America. It is one of the most arboreal grouse, fairly well adapted to perching and moving about in trees. When approached by a predator, it relies on camouflage and immobility to an amazing degree, for example letting people come to within a few feet before finally taking flight, a behavior that has earned it the nickname "fool's hen".
Spruce grouse are 38–43 cm (15–17 in) long; males weigh 550–650 g (19–23 oz) and females 450–550 g (16–19 oz). 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 (red morph) or mottled grey (grey morph) 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 (while the reverse is true in ruffed grouse) and they do not erect their crown feathers when alarmed the way ruffed grouse do.
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 (dead-end extensions of the intestines) increase in size to support digestion. The crop is also well developed: up to 45 cc of needles (about 10% of body mass) 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.