Boreal owls are small raptors that inhabit mixed conifer-aspen forests across Alaska, Canada and northern Eurasia; their range also extends southward through northern Minnesota, the Cascades and the Rocky Mountains. Though widespread and fairly common, boreal owls are rarely encountered, primarily due to their small size and strict nocturnal lifestyle.
When observed, they are generally perched in a conifer, where they spend the daylight hours; identification is made by their small size (females are larger than males), tuftless head, yellow eyes, speckled crown, white facial disc and brown and white plumage. Feeding primarily on mice and songbirds, boreal owls may fall victim to larger owls, fishers or pine martens. Tree cavities are used for nesting and the clutch size varies widely, averaging 5-6 young; the female incubates the eggs while the male guards the site and brings food.
Though widespread in the subalpine forests of Colorado, boreal owls are (in my experience) most commonly observed and reported near Cameron Pass, west of Fort Collins. Of course, this may reflect the large population of birders along the Front Range urban corridor and the accessibility of that relatively low pass (10,300 feet).
