Aegolius
funereus
(Boreal Owl)
Physical
Description:
8 1/2-12" (22-30 cm).
Short-tailed, flat-headed, chubby owl; lacks ear tufts and very tame. Chocolate
brown with fine white spots thickly crowded on head. Large facial disk is pale
grayish with dark border, yellow eyes, and yellow bill. Immature is dusky brown;
eyebrows dirty whitish or gray; belly obscurely blotched.
Similar Species- Northern Saw-whet Owl, Hawk Owl, Northern Pygmy-owl, Screech-owls
Song:
Spring call is similar to the
tolling of a soft bell or dripping water. Also a series of high-pitched whistles,
rising slightly.
Distribution:
Breeds from central Alaska,
east across portions of Canada to Labrador and New Brunswick, and south to northeastern
Washington, Idaho, Montana, and northeastern Minnesota, and further south in
mountains to Colorado and New Mexico. Winters mainly in breeding range, and
south irregularly to northern United States.
bogs. Generally found
in spruce/fir in Rockies. In Idaho, nests in mixed conifer, spruce/fir, Douglas-fir,
and aspen stands.
Diet:
Eats mainly small mammals (often
red-backed voles, but also shrews, pocket gophers, and deer mice). Will sometimes
eat birds and insects.
Ecology:
Hunts from perch; captures prey
on ground. caches food. Nests in abandoned
or natural cavity in standing snag in older forests with complex physical structures.
Defends nest site only. roosts in dense cover by day;
forages mostly at night. Idaho study found home range averaged 1451 ha in winter
and 1152 ha in summer. Best foraging habitat was in spruce/fir stands.
2-5 eggs for 25-36 days.
Young fledge at about 27-31 days, are
independent at 5-6 wk, and become sexually mature by 1 yr.
Conservation:
| Element Code: | ABNSB15010 |
| Status: | Protected nongame species |
| Global Rank: | G5 |
| State Rank: | S2 |
| National Rank: | N4 |
Important
State References:
Hayward, G.D., P.H. Hayward,
and E.O. Garton. 1993. Ecology of boreal owls in the northern Rocky Mountains,
USA. Wildl. Mono. 59.