White-crowned Sparrow - Zonotrichia leucophrys

White-crowned Sparrow has a partial preformative molt, and partial prealternate molts. This species is easy to age reliably in fall simply by the head pattern; in spring this is rarely helpful, but wing and tail can be used to age most individuals. Sex can usually be determined only by brood patch / cloacal protuberance during the breeding season, although particularly small or large wing chords (varying by subspecies) may be indicative of sex for a minority of birds.

The five recognized subspecies differ somewhat in appearance and extent of molt, but the overall patterns are sufficiently consistent for ageing/sexing guidelines to apply to all of them.

Quick tips

• Look at the crown - in fall only DCB (AHY) birds have white and black stripes, while FCF (HY) birds have tan and brown stripes; note that after the prealternate molt this feature is generally not helpful, as some FCA (SY) birds may retain a few brown feathers on the crown, but even DCA (ASY) individuals can occasionally have brown feathers on the hindcrown).
• Examine the rectrices - FCF/FCA birds have uniformly narrow and pointed rectrices OR contrastingly fresh and broad central rectrices, while uniformly broad and more rounded rectrices are typical of DCB/DCA (AHY/ASY), but beware that rectrix shape can be quite variable in this species, so use this criteria with caution and place an emphasis on feather condition.
• Check the wing for molt limits - FCF/FCA (HY/SY) birds show a contrast between darker/fresher greater coverts and the paler block of primary coverts, primaries, and secondaries; this tends to be more readily visible in spring.

Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)