Watercolor portrait of Bay-breasted Warbler (Setophaga castanea)

Bay-breasted Warbler

Setophaga castanea
A long-distance migrant Breeds mainly in mature boreal coniferou… Uncommon High, thin breeding song

Learn to identify the Bay-breasted Warbler by ear. Master the "tsi tsi tsi tsi tsi" phrase and tell it apart from similar species.

“tsi tsi tsi tsi tsi”

What the Bay-breasted Warbler sounds like

A small, compact wood-warbler of the boreal forest, the Bay-breasted Warbler is most striking in breeding plumage, when males show a rich chestnut throat, flanks, and crown patch set against a dark face and creamy buff neck. Outside the breeding season it becomes much duller—olive above with buffy underparts—making it one of the trickier fall warblers to identify. It is best known as a migrant through eastern and central North America and as a spruce-fir breeder in Canada and the northeastern United States.

“tsi tsi tsi tsi tsi”

How to tell it apart

Listen for:A weak, high, thin series of short notes, often slightly buzzy or lisping. It can sound similar to Blackpoll Warbler but is usually slower, lower, and less relentlessly sibilant. Often written as “tsi tsi tsi tsi tsi”.
Don't confuse with:The Blackpoll Warbler — usually shows crisper streaking on the flanks and back in fall.

Where you'll hear it

Breeds mainly in mature boreal coniferous and mixed forests, especially spruce and fir, often where spruce budworm outbreaks provide abundant food. During migration it uses a wide range of wooded habitats including deciduous forests, forest edges, parks, and shelterbelts. It winters primarily in tropical forests, woodland edges, and shaded coffee plantations in northern South America and parts of Central America.

Most noticeable in spring and fall migration, when it passes through the eastern half of North America. It breeds from late spring into summer in northern conifer forests. Fall birds are often overlooked because nonbreeding plumage is subdued and easily confused with other warblers, especially Blackpoll Warbler.

Similar species

Blackpoll Warbler

Usually shows crisper streaking on the flanks and back in fall.

Chestnut-sided Warbler

Breeding Chestnut-sided has a bright yellow crown and bold black facial markings, unlike the darker-faced Bay-breasted male.

Cape May Warbler

Cape May has a thinner, slightly decurved bill and often more obvious facial pattern.

Bay-breasted Warbler song FAQ

What does a Bay-breasted Warbler sound like?
A weak, high, thin series of short notes, often slightly buzzy or lisping. It can sound similar to Blackpoll Warbler but is usually slower, lower, and less relentlessly sibilant. Listen for the "tsi tsi tsi tsi tsi" phrase.
How do I tell a Bay-breasted Warbler from a Blackpoll Warbler by sound?
Blackpoll Warbler: Usually shows crisper streaking on the flanks and back in fall.; Often appears colder gray-green and less buffy overall.; Typically has bright orange to yellowish legs, whereas Bay-breasted tends to look warmer and more buff underneath.; Spring males are black-and-white with a black cap, unlike the chestnut-rich Bay-breasted male..
When is the best time to hear a Bay-breasted Warbler?
Most noticeable in spring and fall migration, when it passes through the eastern half of North America. It breeds from late spring into summer in northern conifer forests. Fall birds are often overlooked because nonbreeding plumage is subdued and easily confused with other warblers, especially Blackpoll Warbler.