Photo: Brian E. Small/Vireo

Swainson's Thrush

Catharus ustulatus

During the peak of migration, Swainson's Thrushes are often very common in woodlots and parks, lurking in the thickets, slipping into fruiting trees to pluck berries. Although they tend to stay out of sight, the patient birder eventually can see them well enough to discern the bold buffy eye-rings that give these birds their alert or startled look. Like the other brown thrushes, Swainson's migrate mostly at night, and their distinctive callnotes can be heard from overhead on clear nights during spring and fall.
Conservation status Has declined as a breeding bird along parts of the Pacific Coast and elsewhere. Overall populations probably stable. Could be vulnerable to loss of habitat on breeding grounds.
Family Thrushes
Habitat Spruce forests and dense streamside woods; in migration, other woods. Breeds in far north and in mountains in coniferous forest with extensive leafy undergrowth; on Pacific Coast, also breeds in deciduous trees and thickets growing along streams. Occurs in many kinds of woodlands in migration. Winters in tropical forest.
During the peak of migration, Swainson's Thrushes are often very common in woodlots and parks, lurking in the thickets, slipping into fruiting trees to pluck berries. Although they tend to stay out of sight, the patient birder eventually can see them well enough to discern the bold buffy eye-rings that give these birds their alert or startled look. Like the other brown thrushes, Swainson's migrate mostly at night, and their distinctive callnotes can be heard from overhead on clear nights during spring and fall.
Photo Gallery
  • adult Olive-backed
  • adult Olive-backed
  • adult Russet-backed, Western coastal
Feeding Behavior

Does much feeding on ground, but not as much as the other brown thrushes. Also forages in trees, and may hover momentarily to take insects from foliage or may catch them in mid-air.


Eggs

3-4, rarely 5. Pale blue, with brown spots sometimes concentrated at larger end; sometimes almost unmarked. Incubation is by female, about 12-14 days. Young: Both parents feed the nestlings. Young leave the nest about 10-13 days after hatching.


Young

Both parents feed the nestlings. Young leave the nest about 10-13 days after hatching.

Diet

Mostly insects and berries. In North America, feeds on a variety of insects including beetles, ants, caterpillars, crickets, wasps, flies, moths, and others, also spiders and other invertebrates. Berries and fruits amount to over one-third of summer diet. Winter diet in tropics not well known, but often found in fruiting trees there.


Nesting

Male arrives on breeding grounds and establishes territory, defending it by singing. In aggressive display during encounters with intruders on territory, he sleeks down his feathers and points bill up. Nest: Usually placed on a horizontal branch, 2-10' above the ground, sometimes lower or much higher (rarely up to 30'). Often nests in conifers in the east and north, deciduous trees or shrubs in the west. Nest (built by female alone) is a bulky open cup of twigs, bark strips, moss, grass, leaves, sometimes with some mud added. Lined with bark fibers, lichens, animal hair, other soft materials.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Spring migration relatively late and spread over a long period, some northbound birds still passing through southern states at beginning of June.

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Migration

Spring migration relatively late and spread over a long period, some northbound birds still passing through southern states at beginning of June.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon
Songs and Calls
Song a series of reedy spiraling notes inflected upward.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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