Warbling Vireo Identification

The Four Keys to ID

  • Size & Shape

    Warbling Vireos are small, chunky songbirds with thick, straight, slightly hooked bills. They are medium-sized for vireos, with a fairly round head and medium-length bill and tail.

    Relative Size

    Slightly larger than a Black-capped Chickadee; smaller than a House Finch.

    Relative Sizesparrow or smallersparrow-sized or smaller
    Measurements
    • Both Sexes
      • Length: 4.7-5.1 in (12-13 cm)
      • Weight: 0.3-0.6 oz (10-16 g)
      • Wingspan: 8.7 in (22 cm)

Regional Differences

Western birds tend to be a bit drabber than eastern birds, though plumage color varies more with season than from east to west. Western birds also have slightly longer bills, but this difference is only rarely useable in the field. The two forms have similar, but diagnosably different songs, western birds having higher-pitched, less “sing-songy,” less caroling, and slightly longer songs than those of eastern birds. The two forms meet near the western edge of the Great Plains, and both forms breed in, at least, Colorado.