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Number of species: 80

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Philadelphia Vireo - Vireo philadelphicus

Age of Philadelphia 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.

Philadelphia and Warbling Vireos can be very similar in appearance; Philadelphia Vireo can generally be distinguished by having dark gray lores, and with yellow across the underparts, brightest on the centre of the breast.

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 greenish-gray 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 pinkish to whitish, while on AHY birds it is usually gray.

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 
Hatch year / Unknown
Subtle molt limit between grayish primary coverts and somewhat fresher and greener greater coverts; rectrices relatively narrow and pointed; roof of mouth pinkish to whitish.
Thumbnail - MG2-2500-65707-Vireo_philadelphicus_AOU_7_52-3633.jpg Thumbnail - MG2-2500-65707-Vireo_philadelphicus_AOU_7_52-3631.jpg Thumbnail - MG2-2500-65707-Vireo_philadelphicus_AOU_7_52-3632.jpg
Date: Aug 28
After hatch year / Unknown
Primary and greater coverts, primaries, and secondaries similarly greenish-gray; rectrices relatively broad and rounded; roof of mouth gray.
Thumbnail - MG2-2500-65821-Vireo_philadelphicus_AOU_7_52-3636.jpg Thumbnail - MG2-2500-65821-Vireo_philadelphicus_AOU_7_52-3634.jpg Thumbnail - MG2-2500-65821-Vireo_philadelphicus_AOU_7_52-3635.jpg
Date: Sep 7
Second year / Unknown
Subtle molt limit between grayish primary coverts and somewhat fresher and greener greater coverts; rectrices relatively narrow and pointed.
Thumbnail - MG2-2650-41389-Vireo_philadelphicus_AOU_7_52-3639.jpg Thumbnail - MG2-2650-41389-Vireo_philadelphicus_AOU_7_52-3637.jpg Thumbnail - MG2-2650-41389-Vireo_philadelphicus_AOU_7_52-3638.jpg
Date: May 24
After second year / Unknown
Primary and greater coverts, primaries, and secondaries similarly greenish-gray; rectrices relatively broad and rounded.
Thumbnail - MG2-2500-65310-Vireo_philadelphicus_AOU_7_52-3642.jpg Thumbnail - MG2-2500-65310-Vireo_philadelphicus_AOU_7_52-3640.jpg Thumbnail - MG2-2500-65310-Vireo_philadelphicus_AOU_7_52-3641.jpg
Date: May 20

Additional age / sex class descriptions

The following additional age / sex class descriptions were found for this species:
Age / Sex   Age / Sex class description
Juvenile / Unknown Brownish-green above and buffy-whitish below, with wing bars.
Number of species: 80

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