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Status: Population size: 14 million Photo by Glen Tepke.

Wood Thrush
(Hylocichla mustelina)

One of our most beautiful songsters, the Wood Thrush breeds in the deciduous forests of eastern North America, where its flute-like melodies can be heard at dawn and dusk. This species has shown a significant decline across its breeding range since the mid-1960s, and it faces continuing degradation and destruction of its forest habitat on both its North American breeding grounds and Central American wintering grounds. Increased forest fragmentation on Wood Thrush's breeding grounds results in higher rates of nest predation and cowbird brood parasitism, thereby decreasing reproductive success.

Identification
The Wood Thrush's melodic "Ee-oh-lay" song alerts visitors to its presence; this species is easier to hear than see. Sexes are alike in this robin-sized bird. Distinct features include the warm reddish-brown color of the crown and nape (fading to olive-brown on the back and wings), the white underparts, and the bold, dark spots on the throat, breast, and flanks. The Wood Thrush also has pink legs and a white eye-ring.

Distribution and Population Trends
Wood Thrush breeds across most of eastern North America, ranging from the panhandle of Florida northward to southern Canada. The species generally reaches its western limit at the eastern edge of the Great Plains, although it can be found breeding along the Missouri River through central South Dakota. Many Audubon Important Bird Areas (IBAs) throughout the eastern United States provide nesting habitat for Wood Thrush, including North Carolina's Eno River Bottomlands IBA and Delaware's Coastal Zone IBA. The Wood Thrush winters mostly in primary, broad-leaved forests at lower elevations from southern Mexico to western Panama.

Across Wood Thrush's entire range, Breeding Bird Survey data from 1966 to 1994 show a decline of 1.7% per year. At one spot on the bird's wintering grounds in Veracruz, Mexico, numbers of Wood Thrush in 1985 were estimated to make up only 30% of the species' abundance there in 1960.

Ecology
Wood Thrush breeds in the interior as well as the edges of deciduous and mixed forests, often near water. It needs moderate to dense understory, shade, moist soil, and decaying leaf litter. This species will sometimes choose shrubby second-growth forests or even suburban parks in which to nest. The female builds a cup nest similar to an American Robin's nest, and typically lays three to four pale blue eggs. The female is responsible for incubation, which lasts about two weeks, but both parents feed nestlings, which remain in the nest for about two weeks. Breeding pairs may raise two broods of young in a single nesting season. Wood Thrush is a fairly common host of Brown-headed Cowbird eggs; the effects of brood parasitism on Wood Thrush reproductive success are most extreme in fragmented forests of the Midwest.

Wood Thrushes forage primarily on the ground, eating a wide variety of invertebrates including beetles, ants, moths, caterpillars, millipedes, and isopods. Birds also feed upon fruits and berries. Wood Thrush begins departing from its breeding grounds in late August and completes migration to its Central American wintering grounds by late October. The species migrates primarily at night, and can be identified and censused by its distinctive nocturnal flight call.

Threats
Wood Thrush has become a species of conservation concern, and in the process, it has been established as a symbol of the decline of Neotropical songbirds in the forests of eastern North America. This species, along with many others, faces threats on both its North American breeding and Neotropical wintering grounds. Forest fragmentation in North American forests results in increased nest predation and increased cowbird parasitism for Wood Thrushes nesting in fragmented forest, thereby significantly reducing their reproductive success. The continuing destruction of primary forest in Central America eliminates preferred Wood Thrush wintering habitat, most likely forcing birds to attempt to exist in secondary habitats where mortality rates may be higher.

Conservation
Wood Thrush is listed as a priority species in Partners in Flight's "Bird Conservation Plan for the Ohio Hills," one of the very few areas where populations of the species have been stable (http://www.partnersinflight.org). One of the objectives of this plan is to ensure the availability of about 2.5 million hectares of deciduous forest to support 725,000 breeding pairs of Wood Thrush.

What Can You Do?
Audubon's Important Bird Area program is a vital tool for the conservation of Wood Thrush as well as other species. To learn more about the Important Bird Area programs in North Carolina, Delaware, New York and other states with breeding populations of Wood Thrush, and how you can help, visit: http://www.audubon.org/bird/iba/

Audubon and our partners in conservation coordinated the submission of over two million comments to the U.S. Forest Service in support of the Roadless Area Conservation Rule, which would protect habitat for Wood Thrush and many other species. Unfortunately, implementation of the Rule has been stalled and attempts are being made to weaken it. To help in protecting these vital habitats visit: http://www.audubon.org/campaign/latestnews.html#roadless

The Cornell Laboratory of Ornithology and the USDA Forest Service coordinate Birds in Forested Landscapes, a citizen-science project that links volunteer birders and professional ornithologists in a study of the habitat requirements of North American forest birds, including Wood Thrush. To learn more about Birds in Forested Landscapes, and how you can participate in the project, visit: http://birds.cornell.edu/bfl/

References
Birds in Forested Landscapes Species Account: Wood Thrush (Hylocichla mustelina). Cornell Lab of Ornithology. http://birds.cornell.edu/bfl/speciesaccts/woothr.html

Roth, R. R., M. S. Johnson, and T. J. Underwood. 1996. Wood Thrush (Hylocichla mustelina). In The Birds of North America, No. 246 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D. C.

Sibley, D.A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York. 544 pp.