Black-throated blue warbler
- Length: 4.5 inches
- Small, active, insect-eating bird
- Thin, pointed bill
- Small white patch in wing can be inconspicuous in immatures
- Often found in the understory of forests rather than the canopy
- Black face, throat, and sides
- Remainder of underparts white
- Deep blue crown, nape back and wing coverts
- Immature males similar to adult males but can have a greenish wash
to the upperparts and have a whitish chin
- Gray crown and cheek patch
- White supercilium
- Grayish upperparts
- Dark wings and tail
- Yellowish-white underparts
The male Black-throated Blue Warbler is instantly recognizable. Females
are rather nondescript but the small white patch in the wing is diagnostic.
When this patch is absent, look for the dark cheek patch contrasting with
the white supercilium. The unstreaked underparts and lack of wing bars are
also helpful field marks.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.