Boreal Owl
Aegolius funereus
Small, chunky owl with a large, flat-topped head. Note extensive white spotting and gray face framed in black. Inhabits boreal, highland, and mixed woodlands; nests in tree cavities. Can be very difficult to find by day. At night, listen for fast tooting song, which can be confused with a displaying snipe; note clearer whistled tone and steadier volume. Populations move in response to winter conditions and prey populations, with large numbers moving south of typical wintering range some winters. Sometimes hunts small rodents around bird feeders. In Eurasia, compare with Eurasian Pygmy-Owl, which is smaller, has a less distinct facial disc, and finer spotting. In North America, distinguished from Northern Saw-whet Owl by its colder gray-brown coloration and spotted (not streaked) forehead.
识别特征
The boreal owl is 22–27 cm (8.7–10.6 in) in length and has a wingspan of 50–62 cm (20–24 in). A female is heavier than a male bird and weighs 131–179 g (4.6–6.3 oz) compared with an average of 107 g (3.8 oz) for a male bird. The plumage is brown above, with white flecking on the shoulders and whitish underparts with rust-colored streaks. The head is large with yellow eyes and a dull white facial disc that is sometimes described as giving the owl a "surprised" expression. The beak is a light yellow, rather than dark like its relative the northern saw-whet owl. The ears are asymmetrical in multiple bones, which affects their hunting success. The sexes are similar in appearance. The plumage of young birds is chocolate brown. The boreal owl's flight is relatively noiseless and straight.<p>Its call is similar in sound to the "winnowing" of the North American Wilson's snipe.
分类信息
The boreal owl was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae. Linnaeus placed it with all the other owls in the genus Strix and coined the binomial name Strix funerea. The Eurasian scops owl is now placed in the genus Aegolius that was introduced in 1829 by the German naturalist Johann Jakob Kaup with the boreal owl as the type species. The genus name is Latin for a screech owl, the word came from the Ancient Greek aigōlios meaning "a bird of ill omen". The specific epithet funereus is Latin meaning "funereal".<p>Seven subspecies are recognised:
- 学名
- Aegolius funereus
- 命名信息
- (Linnaeus, 1758)
- 目
- Strigiformes
- 科
- Strigidae
- 属
- Aegolius
分布与栖息地
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. 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.
- 迁徙
- Nomadic
行为
Migration pattern: Nomadic.
保护状况
Population trend: stable.
- 种群趋势
- stable
照片
分布
鸟叫声
其他鸟类
Ecuadorian Seedeater
Amaurospiza aequatorialis
Scarce and very local. A rather plain, easily overlooked, small seed-eating bird. Usually found as singles or pairs in association with seeding bamboo in forested areas from lowlands to highlands, perhaps most numerous at mid-elevations. Male is dull dark bluish and female is rich brown overall. Note the stout grayish bill with curved culmen. Listen for sharp metallic chips and sweet warbling song.
Western Grasswren
Amytornis textilis
Small brownish bird with fine white streaking and long cocked tail, found in dense coastal shrubland of the Shark Bay area of Western Australia and the northeastern Eyre Peninsula in South Australia near Whyalla (two different subspecies). Upperparts brownish, with paler buff-brown belly. Much more solidly built than fairywrens, with fine white streaks on head and chest. Forages on the ground, darting between shrubs.
Western Kingbird
Tyrannus verticalis
Fairly large yellow-bellied flycatcher; common and widespread in western North America. Rather pale gray head with weakly contrasting whitish throat and breast, and lemon-yellow belly. Also look for black tail with white edges (but this can be difficult to see, especially when worn). Found in open habitats with tall shrubs and trees, often perched up conspicuously on a telephone wire or fence post. Compare especially with Cassin’s Kingbird, which is darker and more contrasting on the head. Winters in large numbers south to Costa Rica, often gathering in large loose groups during migration.
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