A medium boreal warbler.

Also called: Bay-breasted

Native status: Native; boreal breeder

§ Quick facts

SizeBody 13–14 cm (5.1–5.5 in); wingspan 23 cm
Weight12–17 g
LifespanWild typically 5+ years; oldest documented 9
OrderPasseriformes
FamilyParulidae

§ Encyclopedia

The bay-breasted warbler 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.

Source: Wikipedia — Bay-breasted warbler Licensed under CC BY-SA 4.0

§ Identification

Field marks. Males breeding: chestnut crown, throat, sides; black face mask; pale yellow neck patch. Females and immature/winter males: olive-gray above, white below with faint streaks — superficially similar to Blackpoll Warbler.

Similar species. Blackpoll Warbler (more distinct streaking, pink/yellow legs vs. dark legs). Chestnut-sided Warbler (yellow crown, white belly). Pine Warbler (yellow throat, plain face).

Voice. High-pitched buzzy "tseet tseet tseet" — easy to miss.

§ Diet & behavior

Diet. Caterpillars (especially spruce budworm), beetles, true bugs, spiders.

Behavior. Specialist on spruce budworm — populations boom during budworm outbreaks (which occur every 30–40 years) and crash during budworm lulls. Breeds in mature spruce-fir forests across boreal Canada. Migrates to northern South America. Adult males's rich chestnut crown, throat, and flanks contrast strikingly with creamy underparts in breeding plumage.

§ Range

Boreal Canada in summer

§ Habitat

Mature boreal forests

§ Threats

Boreal forest loss.

§ Conservation status

According to the IUCN Red List, the bay-breasted warbler is currently classified as Least Concern.

§ What helps

Support boreal forest conservation.

Support our work More ways to help

§ Further reading

§ Sources cited

  • Cornell Lab — All About Birds
  • Boreal Songbird Initiative
  • iNaturalist
  • IUCN Red List 2018