Alder Flycatcher - Empidonax alnorum

The molt strategy of Alder Flycatcher remains somewhat unclear. What is known is that all molt occurs on the winter grounds; the preformative molt appears to be incomplete to possibly complete in some individuals, while a distinct prealternate molt is likely absent. Sexes are identical in plumage; breeding females have a brood patch, but males have a poorly developed cloacal protuberance and may be more difficult to identify with confidence.

Alder and Willow Flycatcher are nearly identical in appearance and are usually identified reliably only through vocalizations; collectively they are referred to as Traill's Flycatcher. The description in this account likely applies also to eastern Willow Flycatcher, but not to western Willow Flycatcher.

Quick tips

• Look at the wing bars, which are buffy on FCJ (HY) individuals but whitish on older M-FCF (AHY) birds.
• Examine the rectrices, which are narrow and pointed on FCJ (HY) birds, but broader and more rounded on M-FCF (AHY) individuals.
• Check for an eccentric molt limit among the primaries and secondaries, with retained faded juvenile feathers among the inner primaries and/or outer secondaries indicating FCA (SY) from spring through fall.

Species account prepared by McGill Bird Observatory (2018). Last updated by Marcel Gahbauer (Mar 2022)