Boreal owl

Description

The boreal owl is 22–27 cm (8.7–10.6 in) long with a 50–62 cm (20–24 in) wingspan. It is brown above, with white flecking on the shoulders. Underparts whitish streaked with rust. The head is large, with yellow eyes and a white facial disc, and a "surprised" appearance. The beak is light yellow colored rather than dark like its relative the northern saw-whet owl. Their flight is relatively noiseless and straight. Young birds are chocolate brown.

Behaviour

The boreal owl is an unsociable nocturnal owl. Its call is similar in sound to the "winnowing" of the North American Wilson's snipe. This species is not normally migratory, but in some autumns significant numbers move further south. It is rarely any great distance south of its breeding range, although this is partly due to the problems of detecting this nocturnal owl outside the breeding season when it is not calling.

Breeding

The boreal owl breeds in dense coniferous forests across northern North America and the Palearctic, and in mountain ranges such as the Alps and the Rockies. It lays 3–6 eggs in a tree hole. Across much of Europe, and to a lesser extent in Asia and North America, naturalists and biologists put up nest boxes for these and other small owls.

Feeding and diet

This small owl eats mainly voles and other mammals but also birds as well as insects and other invertebrates. It is largely nocturnal, though in the northernmost parts of its range, it is forced to hunt during daylight because of the very short nights in summer.

Mortality

Banded boreal owls have been known to live up to 16 years. Due to the owl's small stature it is often preyed upon by other owls and large raptors thus decreasing its average life span.

Subspecies

Boreal owls have seven subspecies:

• A.f funereus (Linnaeus, 1758): nominate subspecies, from Scandinavia down south to the Pyrenees and east to the Urals, but not the Caucasus Mountains
• A.f. richardsoni (Bonaparte, 1838): the North American subspecies, from Alaska down the Rocky Mountains and as far east as Southeastern Canada and the American Northeast
• A.f. pallens (Schalow, 1908): from southeastern Siberia to Tien Shan in China
• A.f. caucasicus (Buturlin, 1907): Caucasus Mountains
• A.f. magnus (Buturlin, 1907): from Eastern Siberia from Kolyma to the Kamchatka peninsula
• A.f. sibiricus (Buturlin, 1910): widespread over Siberia
• A.f. beickianus Stresemann, 1928: from Northwest India to western China