Wood Thrush
(Hylocichla mustelina)
Cool fact: In the early part of this century, the Wood Thrush's breeding range gradually expanded northward. In Maine, this expansion was often at the expense of two other forest thrushes, the Veery and the Hermit Thrush, both of which are dominated by the Wood Thrush. At the beginning of the breeding season, male Wood Thrushes defend their newly established territories against Veeries and Hermit Thrushes, and these two species are then forced to move to habitats other than those preferred by Wood Thrushes.

Listen to a recording of a Wood Thrush from the Library of Natural Sounds:

Wood Thrush illustration by Larry McQueen
The Wood Thrush inhabits a wide variety of deciduous and mixed forests throughout eastern North America. This thrush ranges during the breeding season from southern Quebec and Ontario to northern Minnesota and Michigan, and south to northern Florida, the Gulf Coast, and southeastern Texas. Features of good Wood Thrush habitat typically include tall trees providing shade, a shrub subcanopy layer, and a fairly open forest floor with leaf litter. The species’ preferred habitat falls between that of the Veery (Catharus fuscescens) and the Hermit Thrush (C. guttatus). Veeries are found most often in areas with shorter trees, more shrubs, and less leaf litter. Hermit Thrushes dwell in forests with denser stands of mid-sized trees and greater canopy cover.

Wood Thrushes may often be found near water where they forage for favored invertebrate prey such as beetles, flies, millipedes, earthworms, spiders, and sow bugs in the moist soil and fallen leaves. Most of their animal food is taken on the ground where leaves are overturned to expose hidden prey. They may also occasionally glean insects from the leaves of low shrubs and trees. In summer, 60 percent of the Wood Thrush diet consists of animal food. At all times of the year small fruits and berries are important, including the fruit of dogwood, spicebush, grape, blackberry, blueberry, holly, elderberry, Virginia creeper, and pokeberry. Young are fed both insects and berries.

In spring, returning males arrive before females and begin to establish territories ranging in size from one-fifth of an acre to two acres. Early in the season males sing from perches high in the tallest trees, but as the breeding season progresses they sing from lower perches and sing somewhat shorter and less-elaborate songs. Each day's singing begins and is most intense just before sunrise. Males may sing throughout the day and especially again at dusk. The season of song is usually over by the end of July. Wood Thrushes are justly famous for their beautiful flute-like voices that may combine two notes at one time. The song is composed of three distinct parts. The first, often inaudible unless the listener is close, consists of two to six short low-pitched notes such as bup, bup, bup. The middle part is a loud phrase often written ee-oh-lay, and the final part is a sometimes ventriloquial, trill-like phrase made up of nonharmonic pairs of notes given quite rapidly and simultaneously. Each bird has a repertoire of songs based on combinations of variations of the three parts, and the songs are often repeated in order. The bup, bup, bup phrase is also heard as a call, which is given louder and at a greater frequency when the bird is agitated.

For nest sites, Wood Thrushes choose dense patches of vegetation that provide concealment and shade. The nest is usually built in a crotch or at a fork in a horizontal branch. The nests resemble those of American Robins (Turdus migratorius), incorporating mud and dead grass, but may be distinguished from those of robins by the presence of dead leaves tucked into the bottom of the nest. Nest building and incubation are female tasks, but both parents help feed the nestlings. Nests are not reused. Typically, two broods are attempted, although three to four separate nests may be built during a season before success is met. About 50 percent of Wood Thrush pairs successfully raise two broods.

Beginning in mid-August, Wood Thrushes begin to migrate south, flying primarily at night. Stragglers may remain in their range into October and November, but there is no evidence of winter survival in the breeding range. After stopping over on the Gulf Coast for two to three days, or longer in inclement weather, they fly across the Gulf of Mexico to winter in the lowland tropical forests of southern Mexico and Central America. The return trip brings them to the Gulf Coast beginning in early April, and from there they move rapidly north, with most birds displaying strong fidelity to the previous year's range.

In recent years, the Wood Thrush, like many other Neotropical migrants, has undergone an alarming population decline. A number of causes have been suggested, including habitat loss in its winter range and forest fragmentation in its breeding range. Forest fragmentation can lead to increased nest predation and cowbird parasitism.

Description:  Wood Thrushes are relatively large thrushes (approximately 7.25 inches in length). The upperparts are bright rufous on the head and nape, shading to cinnamon brown on the back and wings and to olive on the uppertail coverts and tail. The sides of the head are streaked buffy white. There is a conspicuous white eye ring. Underparts are white with large, round dark spots on the breast and sides of the throat that extend along the flanks. The eyes are dark, the upper mandible is black, the lower mandible is pale horn with a dark tip, and the legs are pale pink. Both sexes look alike.

The similarly brown-backed Veery and Hermit Thrush can be distinguished by their smaller size and the location of the brightest coloring on their upper parts. Although the Wood Thrush is brightest on its head and nape, the Hermit Thrush has the warmest coloring on its tail, and the upperparts of the Veery are uniformly colored. Both thrushes, as well as the more olive-colored Gray-cheeked Thrush (Catharus minimus) and Swainson's Thrush (C. ustulatus), have smaller, much-less extensive, and less-distinct spots.

Recording credit:
Wood Thrush song and call recorded by Arthur A. Allen and Peter Paul Kellogg and included on the Peterson Guide to Eastern and Central Bird Songs.

Copyright© 1999 Cornell Laboratory of Ornithology


 

 

 

Wood Thrush photo (detail) by J. R. Woodward slide# 468.1 (JPEG)