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Number of species: 72

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Warbling Vireo - Vireo gilvus

Age of Warbling Vireos can often be determined by molt limits and condition of rectrices, but especially by spring there are many individuals for which these features appear intermediate, and age is not reliably assessed beyond AHY. Determination of sex is limited to brood patch / cloacal protuberance during the breeding season.

Warbling and Philadelphia Vireos can be very similar in appearance; Warbling Vireo can generally be distinguished by having pale gray lores, and with any yellow below brightest on the sides and flanks.

Quick Tips:

  • Examine the primary coverts, which on HY/SY birds are somewhat paler than the greater coverts, while on AHY/ASY both feather tracts are similarly grayish in appearance.
  • Look at the outer rectrices - on HY/SY birds they are narrow and pointed, while on AHY/ASY birds they are more broad and rounded.
  • In fall, check the upper mandible lining - on HY birds it is whitish to pale gray, while on AHY birds it is usually darker gray.
  • Consider the shape and length of p10 relative to the primary coverts - on HY/SY birds it is somewhat longer than the primary coverts, while on AHY/ASY birds it is similar to the primary coverts in length.

Species account prepared by McGill Bird Observatory

Click on any image below to bring up the side-by-side comparison tool.
Age / Sex  Image sets 
Juvenile / Unknown
Brownish-gray above and whitish below, with faint buffy wing bars.
Thumbnail - MH3-2500-65516-Vireo_gilvus_AOU_7_52-3663.jpg Thumbnail - MH3-2500-65516-Vireo_gilvus_AOU_7_52-3661.jpg Thumbnail - MH3-2500-65516-Vireo_gilvus_AOU_7_52-3662.jpg
Hatch year / Unknown
Subtle molt limit between grayish primary coverts and somewhat fresher and greener greater coverts; rectrices relatively narrow and pointed; p10 longer than primary coverts; roof of mouth whitish to pale gray.
Thumbnail - MG2-2640-18636-Vireo_gilvus_AOU_7_52-3645.jpg Thumbnail - MG2-2640-18636-Vireo_gilvus_AOU_7_52-3643.jpg Thumbnail - MG2-2640-18636-Vireo_gilvus_AOU_7_52-3644.jpg
After hatch year / Unknown
Primary and greater coverts, primaries, and secondaries similarly greenish-gray; rectrices relatively broad and rounded; p10 similar in length to primary coverts; roof of mouth dark gray.
Thumbnail - MG2-2510-81327-Vireo_gilvus_AOU_7_52-3651.jpg Thumbnail - MG2-2510-81327-Vireo_gilvus_AOU_7_52-3649.jpg Thumbnail - MG2-2510-81327-Vireo_gilvus_AOU_7_52-3650.jpg
Second year / Unknown
Subtle molt limit between grayish primary coverts and somewhat fresher and greener greater coverts; rectrices relatively narrow and pointed; p10 longer than primary coverts.
Thumbnail - MG2-2650-41394-Vireo_gilvus_AOU_7_52-3657.jpg Thumbnail - MG2-2650-41394-Vireo_gilvus_AOU_7_52-3655.jpg Thumbnail - MG2-2650-41394-Vireo_gilvus_AOU_7_52-3656.jpg
After second year / Unknown
Primary and greater coverts, primaries, and secondaries similarly greenish-gray; rectrices relatively broad and rounded; p10 similar in length to primary coverts.
Thumbnail - MG2-2600-16020-Vireo_gilvus_AOU_7_52-3660.jpg Thumbnail - MG2-2600-16020-Vireo_gilvus_AOU_7_52-3658.jpg Thumbnail - MG2-2600-16020-Vireo_gilvus_AOU_7_52-3659.jpg
Number of species: 72

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