HABITAT: Inhabits much of the northern open coniferous or mixed forests, forest edges, clearings, old burns, dense brushy areas (especially tamarack), scrubby second-growth woodlands, and muskeg.
SPECIAL HABITAT REQUIREMENTS: Open woodlands with cavities for nesting.
NEST: Usually nests in natural cavities or in enlarged holes of pileated woodpeckers and flickers, but also in birch, spruce, and poplar snags. Occasionally nests on cliffs or in crow's nests.
FOOD: Hunts extensively during the day, preying on small mammals (especially mice), birds, and insects. In summer, consumes primarily small mammals and insects. Preys on ptarmigan during winter when other foods are scarce.
REFERENCES: Bent 1938, Henderson 1919, 1925, Mendall 1944.