Qualifies for the list as a Declining Yellow List Species

Photo: USFWS

The Wood Thrush nests in eastern North America from northern Florida to east Texas and north to the upper Midwest and southern Canada. In winter it is found in Central America south to Panama. Its etherial flutelike song is a familiar sound in eastern deciduous woodlands. Its population, however, has decreased over much of its range over the last 30 years and in fact the Wood Thrush is one of the Neotropical migrant species of most management concern. Breeding Bird Survey data show a significant range-wide decline of 1.7% from 1966 to 1994. As a species dependent on forests with a shrub-subcanopy layer, shade, leaf letter, and moist soil conditions, it has declined in response to the destruction and fragmentation of forests. Though it will nest in 1-ha fragments and semi-wooded suburban areas, birds in smaller fragments of woodland with greater amounts of edge and no forest interior have reduced success because of cowbird parasitism and nest predation from species such as jays, crows, raccoons and domestic cats.

Loss of primary habitats on the wintering grounds may be responsible also for reduced populations; the birds probably do less well in secondary habitats and if forced to wander are subject to higher mortality. Environmental pollution may also play a role. Recent studies at Cornell indicate that increased amounts of acid rain make the Wood Thrush less likely to breed. One reason is that acid rain can cause calcium to leach from the soil, and in an environment of reduced calcium, female birds may lay eggs that are thin, brittle, and porous.