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 the importance of molt and age to numerous behavioral and ecological questions. We examined age-based molt patterns and bill corrugations in eight species of lowland Amazonian hummingbirds. Molt strategies and rates of bill smoothing were similar to those of more well-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 during the first annual cycle. Several species showed evidence of delayed maturation in males in regard to plumage characteristics or bill coloration.