A small warbler with striking sexual dimorphism — males deep blue-gray with black throat and face; females olive-gray. Studies of these birds revolutionized ecological theory.
§ Quick facts
§ Encyclopedia
The black-throated blue warbler is a small passerine bird of the New World warbler family. Its breeding ranges are located in the interior of deciduous and mixed coniferous forests in eastern North America. Over the cooler months, it migrates to islands in the Caribbean and Central America. It is very rarely found in western Europe, where it is considered to be a non-indigenous species. The black-throated blue warbler is sexually dimorphic; the adult male has a black face and cheeks, deep blue upperparts and white underparts, while the adult female is olive-brown above and light yellow below.
Source: Wikipedia — Black-throated blue warbler Licensed under CC BY-SA 4.0
§ Identification
Field marks. Male unmistakable: deep blue above, black face and flanks, white belly, and a white wing 'handkerchief' at the base of the primaries. Females drab olive-brown but keep the small white wing square.
Similar species. Female can suggest a drab vireo or Tennessee Warbler, but the white wing spot is diagnostic when present.
Voice. A husky, rising 'zur-zur-zur-zree' with a buzzy upward inflection.
§ Diet & behavior
Diet. Insects (caterpillars primary), spiders, occasional berries on migration.
Behavior. Males forage deliberately in the shrub layer of mature deciduous forest; strongly tied to dense understory like rhododendron and mountain laurel for nesting.
§ Range
Eastern North American forests in summer; winters Caribbean
§ Habitat
Mature deciduous forests with dense shrub layer
§ Threats
Mature forest loss, understory loss, deer overbrowsing.
§ Conservation status
According to the IUCN Red List, the black-throated blue warbler is currently classified as Least Concern.
§ What helps
Support mature forest conservation. Manage deer populations.
§ Further reading
- Wikipedia — Black-throated blue warbler
- www.allaboutbirds.org — authoritative profile of Setophaga caerulescens
- IUCN Red List — search for Setophaga caerulescens
- GBIF occurrence records
- Encyclopedia of Life — Setophaga caerulescens
§ Sources cited
- Cornell Lab of Ornithology — All About Birds
- National Audubon Society
- iNaturalist
- IUCN Red List
