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Bay-breasted Warbler
Dendroica castanea
Anatomy of a Bird

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.

Range Map My Photos Of This Bird
Š 2003 Cornell Lab of Ornithology
Cool Facts Taxonomic Hierarchy Illustration
  • 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.
Kingdom: Animalia
Phylum: Chordata
     Subphylum: Vertebrata
Class: Aves
Order: Passeriformes
Family: Parulidae
Genus: Dendroica
Species: Dendroica castanea
Photo taken from:
The Sibley Field Guide to Birds of Western North America by David Allen Sibley




Adult Description

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

Male Description

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 Description

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 Description

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

  • Breeding Location: Forest edge
  • Breeding Type: Monogamous, Solitary nester
  • Breeding Population: Abundant
  • Egg Color: White, green or blue with purple or brown marks
  • Number of Eggs: 4 - 6
  • Incubation Days: 12 - 13
  • Egg Incubator: Female
  • Nest Material: Sticks, grasses, roots, mosses, and stems, lined with pieces of bark and rabbit hair.
  • Migration: Migratory
  • Condition at Hatching: Helpless with sparse brown down.
Body Head Flight
  • Length Range: 14 cm (5.5 in)
  • Weight: 14 g (0.5 oz)
  • Size: Small (5 - 9 in)
  • Color Primary: Gray, Buff
  • Underparts: Buff with red-brown patches on breast and sides.
  • Upperparts: Black-streaked gray.
  • Back Pattern: Striped or streaked
  • Belly Pattern: Solid
  • Breast Pattern: Solid
  • Bill Shape: All-purpose
  • Eye Color: Dark brown in juveniles and adults.
  • Head Pattern: Capped, Plain, Unique pattern
  • Crown Color: Red-brown
  • Forehead Color: Black
  • Nape Color: Black
  • Throat Color: Red-brown
  • Cere color: No Data
  • Flight Pattern: Weak flight on rapidly beating wings.
  • Wingspan Range: 22 cm (8.5 in)
  • Wing Shape: Rounded-Wings
  • Tail Shape: Fan-shaped Tail
  • Tail Pattern: Solid
  • Upper Tail: Black with white on outer feathers.
  • Under Tail: Black with white patches.
  • Leg Color: Gray


Food Habitat
Hovers at flowers and sap wells (made by sapsuckers), catches insects in flight and plucks them from leaves, plucks spiders and trapped insects from spider webs. Flower nectar, small insects, and tree sap. Comes to hummingbird feeders. Breeds in boreal spruce and fir forest. Winters in lowland tropical forest and second growth.
Other Names Similar Species Conservation Status
  • Paruline ā poitrine baie, Fauvette ā poitrine baie (French)
  • Reinita pecho bayo, Reinita castaņa (Spanish)
  • 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.
Populations decreasing over last 20 years, possibly as result of spraying for spruce budworms. Loss of wintering habitat may be a problem.
Video Sources Used To Construct This Page:


  • Dunn, J. L., and Garrett, K. L. 1997. A Field Guide to Warblers of North America. Houghton Mifflin Co., Boston.

  • 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.

All photos Š 2008 Rick Swartzentrover - Free for non-profit use.
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