HY and some SY Red-eyed Vireos can generally be recognized easily by eye colour, but feather differences are more subtle by age than for many other species. While some SY and ASY individuals can be separated as late as September by the condition of the primary coverts, rectrices, and tertials, there are many intermediates throughout spring and summer that are not reliably aged. Determination of sex is limited to brood patch / cloacal protuberance during the breeding season.
Species account prepared by McGill Bird Observatory
|Age / Sex||Image sets|
|Hatch year / Unknown
Iris grayish to brownish; primary coverts and rectrices somewhat narrow and pointed, roof of mouth pinkish to pale gray.
|After hatch year / Unknown
Iris generally red; primary coverts and rectrices rather broad and rounded; roof of mouth dark gray.
|Age / Sex||Age / Sex class description|
|Second year / Unknown||Primary coverts and rectrices somewhat narrow and pointed; iris sometimes brownish.|
|Juvenile / Unknown||Brownish-green above and whitish below, with wing bars; iris brown or gray-brown.|
|After second year / Unknown||Primary coverts and rectrices rather broad and rounded; sometimes a contrast between paler tertials and uniformly darker secondaries.|