An Introduction to Molt Limits: Part III

This adult male was Malheur NWR headquarters on 30 May 2010 (Dave Irons photo)

We figured it best to save the easiest of the three birds for last, so here's a little eye candy. Few North American birds rival the stunning appearance of an adult male Western Tanager in alternate plumage. On a bright sunny day, they can be absolutely aglow. 

In fresh alternate plumage, this species is entirely lemon yellow below, on the lower back and rump, and on the lower neck. The forehead is fire engine red fading to bright reddish-orange behind and above the eye and on the throat. The back of an adult is solid black with none of the pale margins shown by first summer males. As seen on the bird to the right, the wing and tail feathers of alternate-plumaged adult males are very dark dusky chocolate brown (not quite black). These feathers are the only ones that are not replaced during the prealternate molt (Spring 2010), so they are retained from the last prebasic molt, which occurred in the late Summer/early Fall of 2009. Thus the tail and flight feathers are approximately nine months old, while all the other feathers (the really bright ones) are only 2-3 months old at most.

If this three-part series has piqued your interest in molt, suggested reading includes the Peterson Reference Guide to Molt in North American Birds by Steve N.G. Howell and the Identification Guide to North American Birds Part I, by Peter Pyle.