Black-throated Blue Warbler Identification

The Four Keys to ID

• Size & Shape

  Black-throated Blue Warblers are small, well-proportioned birds with sharp, pointed bills. Compared with other warblers, they are fairly large and plump.

  Relative Size

  Larger than a Blue-gray Gnatcatcher, smaller than a Hermit Thrush.

  sparrow-sized or smaller

  Measurements

  • Both Sexes
  • • Length: 4.3-5.1 in (11-13 cm)
    • Weight: 0.3-0.4 oz (8-12 g)
    • Wingspan: 7.5-7.9 in (19-20 cm)

  © Ian Davies / Macaulay Library

• Color Pattern

  Males are midnight blue above and white below with black on the throat, face, and sides. Females are plain grayish olive overall, although some individuals have blue tints on the wings and tail. Both sexes have a characteristic small white square on the wing, sometimes called a “pocket handkerchief.”

• Behavior

  These birds forage in the understory and lower canopy of forests, where they pick insects from the undersides of leaves. Males sing to defend their breeding territories and aggressively chase away rival males.
• Habitat

  Black-throated Blue Warblers are found in larger tracts of hardwood and mixed hardwood-evergreen forests with a shrubby understory.