Sequence of replacement and lengths of primary wing feathers grown by Ash-throated Flycatchers during the prebasic molt. Shown are numbers of feathers indicating molt sequence at each position in the wing. Primary molt begins at P1 and proceeds distally to P10 in juveniles and adults. No feathers showed a distal-to-proximal replacement pattern. Within each age class, primary length (mm) is the mean of five specimens of each sex