PREFORMATIVE MOLT EXTENT AND AGING AND SEXING CRITERIA FOR EIGHT HUMMINGBIRD SPECIES IN SOUTHEASTERN PERU

Abstract

∙ Little attention has been paid to molt and age criteria in hummingbirds despite their importance to numerous behavioral and ecological questions. We documented molt extent, age-specific molt patterns, plumages, percent of the bill with corrugations, the presence or absence of delayed plumage maturation, and bill color changes in males of sexually dichromatic species in eight species of lowland Amazonian hummingbirds. Molt strategies and rates of bill smoothing were similar to those of better-studied North American species, with all species showing partial preformative molts (replacing only body feathers and some wing coverts, and retaining all remiges and rectrices), and bill corrugations reducing to less than 10% of bill length in all species by the time they achieved definitive cycle basic plumage. Several species showed evidence of delayed maturation in males in regard to plumage characteristics or bill coloration.