Timing, pattern, and extent of first prebasic molt of White-winged Crossbills in Alaska

The timing, pattern, and extent of the first prebasic wing molt of White-wi nged Crossbills (Loxia leucoptera) were determined during a 6-yr banding st udy in interior Alaska. Hatching-year birds were not caught in substantial numbers until May, and all crossbills molted from juvenal to first basic pl umage between September and December. A subsample consisting of 65 males an d 55 females in first basic plumage was used to determine the pattern and e xtent of wing covert molt. On average, birds molted three greater coverts ( GC) and retained two juvenal medial coverts (MC) per wing. The number of mo lted GCs was negatively correlated with that of juvenal MCs. Twenty-three p ercent of the individuals molted no GC, and no crossbill replaced all these feathers. The pattern and extent of covert molt was similar in males and f emales and was symmetrical in 69% of the individuals, but differed by one o r two feathers in the remaining birds. Males in first basic plumage and wit h partially red or pink contour feathers molted more GCs and retained fewer MCs than males without contour feathers of these colors, although both gro ups apparently were of the same age. Remex molt was found in only one bird, which also showed partial proximal secondaries (=tertial) replacement.