Grays Harbor Birds — Swainson’s Thrush (Catharus ustulatus)


Few sounds say summer is on the way in the PNW like the sound of the Swainson’s Thrush. Their song is beautiful, an upwardly-spiraling flute-like note, and once you hear it you will be captivated by its beauty. Mother Nature has played a real trick with this bird because you may never see the singer; it is a very shy bird of the dense brush, preferring to sing in solitude. In the 15 plus years I have lived in the PNW I have only seen a Swainson’s once.

So enjoy his song but accept that this photo by Gregg Thompson is probably the only time you will actually see what he looks like! To hear his song, check out Seattle Audubon’s Bird Web site at: http://www.birdweb.org/birdweb/bird/swainsons_thrush and click on “Listen”.

Size: 7 inches long, with a wing span of 12 inches, and weighing only 1.1 ounce

General Description: The Swainson’s is one of three spot-breasted thrushes found in Washington, but the only one to be found here on the Harbor in the summer. Just a bit smaller than a robin, it is a very plain-looking bird, with the Pacific region sub-species a russet-brown on the upper parts, a light-colored belly, and smudgy spotting on the breast. The bill is straight and pointed, with a pinkish color at the base of the lower part. Also distinctive is a buffy eyebrow or eye ring.

Habitat: This thrush prefers the riparian woodland areas of dense alder thickets along streams, and is often found in recently cleared forests where alders and salmonberries have filled in the clearings.

Behavior: The Swainson’s Thrush is generally a solitary bird and can usually be found on the ground in the late spring and summer, feeding amongst the leaf litter. Later in the season the thrush moves off the ground into berry bushes. It spends more time foraging in the trees than the other spot-breasted thrushes, hovering while gleaning insects from leaves and branches. It may also “hawk” insects from tree perches, flying out to grab them from the air. When threatened, a bird may raise its head feathers and aggressively flick is tail feathers.

Diet: The diet of the Swainson’s Thrush is seasonal, with insects starting off the summer when they are first available to the just-arrived and hungry birds. As the berries ripen, they become the main staple of the diet, making up over one-third of their intake.

Nesting: The male thrush sings to establish his territory and attract a mate, and they are a monogamous pair. The female builds the nest, a bulky open cup of twigs, bark strips, moss, grass, leaves and mud, and lines it with animal hair, lichen, and soft grasses. She lays 3 to 4 eggs and incubates them herself for 12 to 14 days. Both parents feed the young which leave the nest 10 to 13 days after hatching.

Migration: Swainson’s Thrushes do not winter in Washington. They arrive here in mid to late May and migrate south beginning in August and September, flying at night, and heading for the tropical forests of coastal Mexico and Central America. They can be found as far south as Argentina.

Conservation Status: Swainson’s Thrush are currently the most abundant and widely distributed of the three spot-breasted thrushes found in Washington. They have actually benefitted from the extensive west-side logging because it leaves great habitat growth behind. There is still concern for habitat loss on their wintering grounds.

When and Where to Find in Grays Harbor: Swainson’s Thrushes are common in recently cut forested areas where shrubs, and salmonberry thickets have begun to fill in the spaces. They can also be attracted to yards where there are no cats or dogs or children playing. Just allow your leaf litter to accumulate on the bare ground, keep a shallow water dish at ground level, and keep a close eye on the area in the summer. Meanwhile, enjoy the marvelous song!

 

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