The bay-breasted warbler (Setophaga castanea) is a small species of songbird in the New World warbler family, Parulidae. It is one of 35 species in the diverse genus Setophaga. Like all songbirds, or passerines, the species is classified in the order Passeriformes.

Taxonomy

The bay-breasted warbler was formally described and illustrated in 1810 by the American ornithologist Alexander Wilson based on specimens collected in Pennsylvania. Wilson coined the binomial name Sylvia castanea. The specific epithet is Latin meaning "chestnut-coloured". The bay-breasted warbler is now one of over 30 species placed in the genus Setophaga that was introduced by the English naturalist William Swainson in 1827. The species is monotypic, with no subspecies accepted. The genus name Setophaga combines the Ancient Greek σης/sēs, σητος/sētos meaning "moth" with -φαγος/-phagos meaning "-eating".

Description

Adult males in breeding plumage are primarily greyish above, with two white wing bars, dark streaks on the back, and a creamy neck patch. The face is black, and the crown, throat, and sides are a dark chestnut colour. Breeding females are similar in overall pattern to the males, but are paler and duller. In the nonbreeding season, both sexes gain olive-green feathers on the back, nape, and head. The rufous on the flanks is limited and may even fade away entirely in nonbreeding females. The two white wing bars are present in all plumages. The species winters in the wet lowland forests of northeastern South America, the Caribbean, and southern Central America, and may be seen during spring and fall migration across the eastern half of the United States in a variety of vegetative communities. Many individuals cross the Gulf of Mexico on their long-distance migration, although some travel north and south along the Mexican shore. It is a rare vagrant west to the west coast of North America, and has also been recorded in Greenland. These are gleaned from vegetation, never caught on the wing. To avoid competition with similar species, bay-breasted warblers concentrate their foraging on the breeding grounds to the interior middle portions of coniferous trees. On wintering grounds in the tropics, fruit forms a majority of the diet. Wintering bay-breasted warblers often form mixed-species flocks with other neotropical migrants and resident species. These flocks seek food in the forest canopy, and the bay-breasted warbler is often an aggressive member of the unit, bullying smaller species from potential food sources.

References

  • Bay-breasted warbler species account - Cornell Lab of Ornithology
  • Bay-breasted warbler - Dendroica castanea - USGS Patuxent Bird Identification InfoCenter