Boreal Owl
Aegolius funereus

The boreal owl illustrates the principal that everything in nature has its niche. Prior to the  early 1980s, scientists knew that this owl nested in boreal forests throughout Canada, but field guides showed its range extending only as far south as the U.S.-Canada border. Biologists at Colorado State University, noting that boreal (subalpine) forests grow along the spine of the Rockies from Canada to New Mexico, began searching for boreal owls in spruce-fir forests on Cameron Pass. In 1982 they found 34 calling males and  Colorado’s first documented nest.

Two years later, Dave Hallock heard a boreal owl near Red Rock Lake, west  of Ward. During ensuing years, BCNA volunteers heard boreal owls in this area and on Bryan Mountain, near Hessie. Biologists now know that this hearty subalpine specialist does, indeed, nest in Rocky Mountain spruce-fir forests from Canada to northern New Mexico.

The boreal owl’s tremulous territorial call haunts subalpine forests from February through May. Females lay three to seven eggs in a woodpecker hole or other tree cavity. Nesting trees are often situated close to open meadows where these nocturnal hunters catch voles and mice, but boreal owls are equally adept at hunting in dense cover. Individuals may migrate downslope in winter, but during the breeding season boreal owls rarely, if ever, leave the subalpine forest.

Boreal owl

Vocalizations: A rising tremulous call, like the “winnowing” of a common snipe, "hoo-hoo-hoo-hoo-hoo”; a synthesizer-like wail or scream.

Nesting: Woodpecker hole or other natural cavity in spruce or fir (above 9,500 feet), April-July.

Where to listen and look: Brainard Lake road and Left Hand Reservoir road, west of Ward; Fourth of July Campground road, west of Eldora.

Cornell McCaulay Library reference