Varied Thrush (Ixoreus naevius)

[order] PASSERIFORMES | [family] Turdidae | [latin] Ixoreus naevius | [UK] Varied Thrush | [FR] Grive a collier | [DE] Halsband-Drossel | [ES] | [NL] Bonte Lijster

Subspecies

Physical charateristics

Male: Characteristics of male Varied Thrushes are a slate blue back and nape, an orange face, eyebrow, and breast with a black eye stripe and black necklace or breast band. Wings; Coverts are slate-grey with two orange bars. Secondaries are slate-grey and tipped with orange. Primaries are slate-grey and dappled with orange.
Female: Resembles the male but much more dull and with brownish-olive coloration replacing the slate-grey of the male

Listen to the sound of Varied Thrush

[audio:http://www.aviflevoland.nl/sounddb/V/Varied Thrush.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

North America : West

Habitat

Varied Thrushes are most commonly found in dense, moist woodlands and low coniferous old growth forests. In California, Varied Thrushes prefer the forests of coastal redwoods, Sitka spruce and red alder; in Oregon and Washington they prefer wet coastal forests of Sitka spruce, western hemlock and western red cedar and wet montane forests with Douglas fir, western hemlock and western red cedar; in northwestern Montana they prefer forests of western larch and Douglas fir; in coastal British Columbia they prefer forests of Douglas fir, western hemlock, western red cedar and Sitka spruce; in interior British Columbia they prefer montane coniferous and taiga forests; and in Alaska they prefer wet coastal and taiga forests.

Reproduction

Varied Thrushes are difficult to study because of their retiring behavior, love of dark, wet forests and low population densities. The males usually choose territories that serve both for breeding and feeding in wet, mature forests. The males establish individual territories by singing. During the breeding season, a male Varied Thrush will chase rival males away from its territory.
Female Varied Thrushes build their nests in low bushes on or near a stream bank. Active nests are often found near old nests in the understory. The nests are three layered with a course outer layer of twigs, leaves, lichen and bark, a dense middle layer of rotten wood and moss or sometimes with mud and wet grass, and a fine inner layer of soft grasses, dead leaves and moss. The eggs are greenish-blue with sparse dark umber-brown spots. Along the coast, females tend to lay an average of 3 eggs with a range of 1 to 5, while the interior subspecies lay an average of 4 eggs with a range of 2-6. They may raise two broods a year and the hatchlings are altricial. Varied Thrushes are monogamous and both parents help feed the young.

Feeding habits

During migration they eat fruits, berries and acorns. During the summer they eat arthropods, fruits and berries. During the winter, Varied Thrushes eat arthropods, fruits and acorns and can be lured to backyard feeding stations and are fond of apples. Some suggest that the population cycling of the Varied Thrush is tied to the fruiting cycle of oak trees in the thrush’s habitat.

Conservation

This species has a large range, with an estimated global Extent of Occurrence of 3,300,000 km2. It has a large global population estimated to be 26,000,000 individuals (Rich et al. 2003). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Migration

Varied Thrushes are altitudinal migrants. They generally breed at middle to high elevations. They head down into the lowlands in winter. In late winter and early spring, they may wander to more open areas, and then in March and April they return to their breeding range. Winter range may depend on severity of weather.

Distribution map