Living Bird Magazine
Swainson's ThrushCatharus ustulatus
- ORDER: Passeriformes
- FAMILY: Turdidae
More likely to be heard than seen, Swainson’s Thrushes enliven summer mornings and evenings with their upward-spiraling, flutelike songs. During fall and spring migration, their soft, bell-like overhead “peeps” may be mistaken for the calls of frogs. These largely arboreal foragers pluck berries, glean bugs from leaves, or perch on branches and stumps. They also bound across the forest floor to catch insect prey. They breed in the north and the mountainous West, but they become very widespread during migration.More ID Info
Find This Bird
During summer, look—and especially listen—for the Swainson’s Thrush and its distinctive, spiraling song in closed forests of northern North America and the West. Swainson’s Thrushes become numerous across most of forested North America during migration in spring and fall. Though these birds can be hard to spot on the ground in a dim forest understory, they sing frequently in summer and call frequently during migration. In the breeding season, listen for the species’ beautiful, flutelike song coming from rich forest. (Just remember that Hermit Thrushes have a similar song, though it usually includes a clear, level introductory note.) Swainson’s Thrush also gives its distinctive water-drip call quite frequently. Once you get eyes on a candidate, check the face for that distinctive buffy-spectacled look. On winter grounds in Central and northern South America, the species inhabits closed-canopy forest and can often be found attending army-ant swarms.
- Zorzalito de Swainson (Spanish)
- Grive à dos olive (French)
If you live within the Swainson’s Thrush’s range, you can make your yard more enticing to this bird by providing tree and shrub cover and ground-level bird baths, avoiding chemical pesticides, and letting leaf litter accumulate undisturbed.
- Cool Facts
- The "russet-backed" Pacific population has more reddish plumage and a slightly different song than the "olive-backed" birds in the rest of the range. The russet-backed birds winter in Central America while the olive-backed ones winter in South America.
- The Swainson’s Thrush’s whirling song has a ventriloqual quality that can make it difficult to track. This may happen as the singer moves quickly from one perch to another between songs. It may also have to do with the sounds’ reverberation in dense foliage. Swainson’s Thrushes also sometimes sing quiet songs that create the illusion that its song emanates from a more distant location.
- Territorial disputes between males often take the form of singing duels, with song volume and frequency escalating until the combatants’ physical exertions are clearly evident. During these contests, rivals very occasionally invert their customary melody so that it spirals downward in pitch. A sing-off can lead to a chase and even occasionally to physical attack.
- Swainson’s Thrushes have been called “mosquito thrushes” for their flycatching habit of going after flying insects while feeding on their breeding grounds.
- In New England spruce-fir forests, the nests of Swainson’s Thrushes are often lined with root-like cords of horsehair fungus. The fungal filaments can have antibiotic effects and may help deter nest pathogens.
- The longest-lived Swainson’s Thrush on record was at least 12 years, 1 month old when it was recaught and rereleased during banding operations in Montana in 2006.