Vancouver Avian Research Centre

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Species: Varied Thrush Ixoreus naevius
 

Description:

This shy thrush with its contrasting black and orange plumage and eerie, penetrating song is one of the most distinctive birds of the Northwestern forests. It breeds from Alaska to California and most individuals winter along the Pacific Coast from Alaska to southern California, with occasional individuals seen throughout the western U.S and, during irruption years across the U.S. and Canada.

Identification:

General: Large, brightly coloured Thrush. Pot bellied, long-necked and short tailed. Length: 19-26cm, weight: 78g.

Adult Male: Burnt-orange breast and throat, gray to blue-gray rump, back, nape and crown, distinct black to slate-gray V shaped breast-band, orange-buffy supercilium stripe and wing-bars, black to slate-gray wing and tail feathers. Bill is brown-black and straw-coloured below at base of lower mandible. Legs are tan and iris brown.

Adult Female: Similar to male but duller overall, with upperparts brown-olive to brown-gray, wing and tail feathers brown, and breast-band indistinct brown to slate.

Juvenile: Head and neck brown tinged with buff, with indistinct orange eyebrow; throat buff; breast feathers buff with brown tips; belly and undertail coverts white; and back and wings brown, with two orange wing-bars.

Similar Species: Dark breast band and orange supercilium distinguish this species from female American Robin and the two species are so different that they are rarely confused. No other North American species is similar in appearance.

Behavior: This is a shy species. It hops along the ground searching for food using its bill to remove leaves and litter and then hops backward to inspect the area for food. When foraging, it searches an area, flies up to a perch and looks for another suitable site to forage before going back to the ground. It may dive and swoop through dense vegetation (sometimes hitting branches) when engaged in territorial fights or when chasing intruders from its nest. Flight from ground or between perches is direct, with rapid wing-beats. It feeds on insects and berries.

Habitat: “A dark forest, with wet, mossy, almost completely shaded floor is a requisite” (Grinnell & Miller 1944:356). This species is closely associated with the damp, shaded coniferous forests of the Pacific North-west. It is also found in ravines and forested urban areas of the north-west.

Information:

This species is a short-distance migrant. While individuals that breed in interior clearly migrate south in winter, it is not clear if coastal breeders are resident or migratory. The few recoveries of banded Varied Thrushes shed little light on migration patterns. During the winter it is often found in flocks.

Nests are built on horizontal branches or in crotches, 10-15 ft high and consist of twigs, dead leaves, mosses, bark and the cup lining of soft leaves and dry grasses. Three to four eggs are laid and are pale blue sparingly dotted with browns.

Conspicuous with this species is its evocative, ethereal song. Males ascend to the tops of trees and utter their song while concealed in the foliage. “There is a legend that warns wanderers of Northwest forests to keep their heads when hearing the preternatural song of the Varied Thrush. If you are alone, if there is a veil of fog hanging from the coniferous branches at a certain slant, the song lulls you into a frame of mind that makes you susceptible to abduction by faeries. Evidently, they will caper you away to their own faery-world, where years may pass in the space of a normal hour.”(L.L Haupt, Rare Encounters with Ordinary Birds).

Conservation:

This not a threatened species although many birds are killed as a result of collisions with windows.

 
Capture Rates


Low capture rates (2010-2012; standardized as birds captured per 100 net hours) of Varied Thrush reflect the fact that Colony Farm is not their preferred habitat. They infrequently occupy the mixed forest of the perimeter of the banding area. Capture of few individuals in April and May reflect movement to suitable breeding areas and in October reflects dispersion and foraging.

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