Boreal Owl

Aegolius funereus (Linnaeus, 1758)

2014-04-09 Sunkar, Almaty region	© Vassiliy Fedorenko

Description

Adult Boreal Owls both males and females are brownish above with white spots on head, neck, shoulders and upper wing coverts. The nape's spots are drop-shaped, rear-neck's spots are larger than on nape, and shoulder's spots are larger than on neck. Back is plain brownish. Primaries are pale-brownish or brownish with white spots on outer and inner webs. Tail feathers are brownish with long pale spots formed five-six pale bars on the furled tail. Head is large. Facial disk is white with brownish streaks near eyes and ears and black spot in front of eye. Breast and belly are pale-grey or whitish with unclear pale-brownish spots. Bill is yellow, claws are black. Tarsus is white, dense feathered. Eyes are yellow. Females are some larger than males. Juveniles are darker than adults. Upperparts are chocolate-brownish or deep rusty-brownish. Head is brownish without pale spots. Throat and craw are brownish, upper-belly is brownish-buffy, lower-belly is with whitish-buffy pattern. Tarsus is white buffy tinged. Sizes: males - wing 145-157 mm, tail 90 mm, bill 10 mm; females - wing 174 mm, tail 93 mm, bill 12,5 mm. Weight 107-140 gr.

Distribution

Lives in the mountain forests of Eastern and South-Eastern Kazakhstan and in uplands of Northern Kazakhstan. On autumn and winter dispersal it also occurs on Ural valley.

Biology

Rare resident. Inhabits spruce, spruce-fir, pine, larch, mixed, or old deciduous forests at up to 2500 m in Tien Shan. Breeds in separate pairs fairly far each of other. Nests in tree holes lined with moss, dry leaves and grass stems, at 3-4 m above ground. Sometimes nest-boxes for Goldeneye occupied too. Clutches of 5-8 eggs, in April – mid-June. Female incubates only, male feeds her and the brood. Fledglings recorded in end June – early July, and up to August they depend from parents. In late autumn (October – November) they lower to foothills and on plains, the spread of disperse may be up to several hundred kilometres.

Subspecies

Aegolius funereus pallens (Schalow, 1908) Description. Upperparts are chocolate-brown rusty-tinged, without grey. White spotting of upperparts less developed than in sibiricus. Dark pattern on underparts is well developed. Distribution. Occupies Tien Shan and Dzhungarskiy Alatau.

Aegolius funereus sibiricus (Buturlin, 1910) Description. Upperparts less brown, more grey than in pallens. White spotting of upperparts more developed, dark pattern on underparts is less developed than in pallens. Distribution. Occupies Kokchetav upland, pine forests in Semipalatinsk area, Altai (Rakhmanovskiye springs), Kalbinskiy Altai. On dispersal occurs in Kurgaldzhino (26 September 1969), in Naurzum Reserve, in lower Ural valley close to Kozhekharovo (23 October 1957) and near Atyrau.

References

"Птицы Казахстана" том 2. "Наука". Алма-Ата, 1962. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999. Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005.