By examining specimens of ptarmigan (Phasianidae: Lagopus spp.), I quantified three discrete periods of molt and three plumages for each sex, confirming the presence of a definitive presupplemental molt. A spring contour molt was significantly later and more extensive in females than in males, a summer contour molt was significantly earlier and more extensive in males than in females, and complete summer-fall wing and contour molts were statistically similar in timing between the sexes. Completeness of feather replacement, similarities between the sexes, and comparison of molts with those of related taxa indicate that the white winter plumage of ptarmigan should be considered the basic plumage, with shifts in hormonal and endocrinological cycles explaining differences in plumage coloration compared with those of other phasianids. Assignment of prealternate and presupplemental molts in ptarmigan necessitates the examination of molt evolution in Galloanseres. Using comparisons with Anserinae and Anatinae, I considered a novel interpretation: that molts in ptarmigan have evolved separately within each sex, and that the presupplemental and prealternate molts show sex-specific sequences within the definitive molt cycle.
Revisión de la Terminología de la Muda y el Plumaje en Lagopus spp. (Phasianidae) con Base en Consideraciones Evolutivas