Bay-breasted Warbler

Dendroica castanea

Order PASSERIFORMES - Family PARULIDAE

Menu

1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

A large warbler of the northern spruce forests, the Bay-breasted Warbler benefits from spruce budworm outbreaks when the caterpillars provide abundant food. Spraying to control the destructive outbreaks may have reduced populations of this warbler.

Cool Facts

• The Bay-breasted Warbler is closely related to the Blackpoll Warbler, and hybrids between the two species are known. The Bay-breasted Warbler is known to hybridize also with Yellow-rumped and Blackburnian warblers.

• Adult Bay-breasted Warblers appear to follow a more western migratory route south in the fall than first-year birds. More adults migrate west of the Appalachian Mountains than east of them, while first-year birds are frequent along the coast.

• In contrast to the more stable populations of other warblers, Bay-breasted Warbler numbers go up and down depending on outbreaks of the spruce budworm. It is abundant during infestations, but declines or even disappears from some areas a few years later.

Description

• Size: 14 cm (6 in)
• Wingspan: 20-22 cm (8-9 in)
• Weight: 10-17 g (0.35-0.6 ounces)

• Small songbird; large warbler.
• Breeding male with black face and chestnut head.
• Two broad white wingbars.
• Rufous on flanks.

• White spots in tail.
• Legs dark.
• Pale side of neck.
• Streaks on back.

Sex Differences

Adult male with chestnut head and flanks, female dull olive green.

Male

Breeding (Alternate) plumage: Crown, throat, and sides deep chestnut brown. Cream colored patch on back of neck. Belly whitish. Back gray with black stripes. Two broad white wingbars on each wing. Undertail coverts buffy. Eye dark. Legs black.
Nonbreeding (Basic) plumage: Crown, nape, and upperparts yellowish olive green, streaked with black. Rump grayish. Flanks striped with chestnut. Indistinct yellow eyestripe. Wings and tail blackish. Two broad white wingbars on each wing. Pale patch on back of neck. Buffy undertail coverts.

Female

Breeding (Alternate) plumage: Sides washed with variable amounts of chestnut. Face gray. Creamy patch on back of neck. Throat buffy, tinged with chestnut. Back olive-gray with indistinct black stripes. Rump olive-gray and unstreaked. Wings with two broad white wingbars. White spots near tip of outer two tail feathers.
Nonbreeding (Basic) plumage: Crown, nape, and upperparts yellowish olive green, streaked with black. Rump grayish. Flanks striped with light chestnut or buff. Indistinct yellow eyestripe. Wings and tail blackish. Two broad white wingbars on each wing. Pale patch on back of neck. Buffy undertail coverts.

Immature

Similar to fall adult, but with less chestnut, more olive, and finer streaking on back. Still shows two broad wingbars and hint of pale neck patch.

Similar Species

• Chestnut-sided Warbler has white chest and yellow-green crown, with the chestnut restricted to two lines down either side of the breast.
• In fall, very similar to Blackpoll Warbler. Blackpoll does not have buffy or rufous along sides, has streaking on underparts, white undertail coverts, more defined eyestripe, and pale legs and/or feet.
• Pine Warbler is unstreaked on back and has white undertail coverts.

Sound

Song very high-pitched "seetzy, seetzy, seetzy."

»listen to songs of this species

Range

Summer Range

Breeds in central and eastern Canada, southward to northern states.

Winter Range

Winters in Panama and northwestern South America.

Habitat

Breeds in boreal spruce and fir forest. Winters in lowland tropical forest and second growth.

Food

Insects and spiders, fruit in winter.

Behavior

Foraging

Gleans insects off leaves and branches in middle part of trees.

Reproduction

Nest Type

Nest an open cup of twigs, bark, lichen, spider web, and plant down; lined with fine rootlets, pine needles, hair, moss, and fine grasses. Placed on limb of dense spruce tree.

Egg Description

White or creamy with bold dark spots.

Clutch Size

4-7 eggs.

Condition at Hatching

Helpless with sparse brown down.

Conservation Status

Populations decreasing over last 20 years, possibly as result of spraying for spruce budworms. Loss of wintering habitat may be a problem.

Other Names

Paruline à poitrine baie, Fauvette à poitrine baie (French)
Reinita pecho bayo, Reinita castaña (Spanish)

Sources used to construct this page:

1. Dunn, J. L., and Garrett, K. L. 1997. A Field Guide to Warblers of North America. Houghton Mifflin Co., Boston.
2. Williams, J. M. 1996. Bay-breasted Warbler (Dendroica castanea). In The Birds of North America, No. 206 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.