Birds
Wood Thrush
Hylocichla mustelina · also called wood thrushes
Deep within a stand of mature eastern deciduous forest, a wood thrush delivers a flute-like song made richer by an ability few other birds share, singing two distinct notes at the same time using both sides of its own voice box.
Overview
The wood thrush, Hylocichla mustelina, is a spotted-breasted songbird native to mature deciduous forest across a broad range of the eastern United States and southeastern Canada, wintering in Central America. Its remarkable two-note simultaneous song, strict dependence on unbroken forest interior, and steep population decline tied to habitat loss on both its breeding and wintering grounds make it one of the more vocally gifted yet conservation-significant songbirds in eastern North America.
A song built from two voices at once
Most birds sing one note at a time, but the wood thrush’s uniquely controlled voice box lets it layer two notes together, producing a richer, more complex song than its simple appearance might suggest.
Status
Least Concern, though declining substantially as breeding forest in the eastern United States is fragmented and wintering forest in Central America is cleared.
Wood Thrush: common questions
How does the wood thrush sing two notes at once?
This species has independent control over the two sides of its syrinx, the vocal organ found in birds, allowing it to produce two different notes simultaneously rather than one note at a time, a capability that gives its song a distinctive layered, flute-like quality considered among the most beautiful of any North American bird.
Why is the wood thrush declining even though it remains widespread?
This species faces pressure on two fronts, with its breeding forests in eastern North America increasingly fragmented by development and its wintering forests in Central America being cleared, a combination that has driven a substantial population decline even though the species has not yet become rare enough to lose its Least Concern status.
Why does the wood thrush keep spotted plumage as an adult?
This species retains a spotted breast pattern into adulthood, an old ancestral thrush trait that continues to help camouflage the bird against dappled forest floor light and leaf litter while it forages on the ground, a pattern many other thrush species also keep for the same reason.
Does the brown-headed cowbird target the wood thrush?
Yes, this species is a frequent target of brood parasitism by the brown-headed cowbird, which lays its own eggs in the wood thrush's nest, leaving the host parents to unknowingly raise the cowbird's chick, often at some cost to the wood thrush's own offspring.