Sex- and age-related differences in post-breeding molt phenology are phylogenetically and ecologically widespread in passerines

Assessment of within-population variation in the timing and duration of molt is crucial to understanding how molt overlaps and interacts with other important phases of the avian annual cycle, including breeding and migration. We investigated the effects of sex and adult age on phenology of the post-breeding prebasic molt in an assemblage of migratory songbird species captured during banding operations at Powdermill Avian Research Center in southwestern Pennsylvania, USA. Across all species examined, males consistently initiated molt earlier than females (14 of 15 species), and young adults hatched the previous year consistently initiated molt earlier than experienced older adults (13 of 13 species). Sex also had a weaker but significant effect on molt duration, with females completing molt more rapidly than males in 67% of the species examined. Adult age, in contrast, had no significant effect on molt duration. A review of the literature indicates that similar patterns are observed in t..., Collection of Molt Data
Molt data analyzed for this study were collected from 1986–2004 in conjunction with year-round mist-netting and bird-banding operations at Powdermill Avian Research Center (40.1637°N, 79.2674°W), the field station of Carnegie Museum of Natural History, in southwestern Pennsylvania, USA. After identifying each captured individual to species and banding it with a uniquely numbered U. S. Bird Banding Laboratory band, we determined its sex using either plumage characteristics (for sexually dimorphic species) or the presence of a brood patch or cloacal protuberance. Adults were age-classified as either SY (second-year birds hatched the previous calendar year) or ASY (after-second-year birds hatched two or more calendar years ago), based on wing molt limits (Mulvihill 1993) and other plumage criteria that have since become standard in passerine aging (Pyle 2022). Each individual was then assigned a total flight-feather molt score (0–90) based on the molt stage of the 1..., # Data from: Sex- and age-related differences in post-breeding molt phenology are phylogenetically and ecologically widespread in passerines

Dataset DOI: [10.5061/dryad.rr4xgxdm9](10.5061/dryad.rr4xgxdm9)

## Description of the data and file structure

Molt data collected at Powdermill Avian Research Center (40.1637°N, 79.2674°W), the field station of Carnegie Museum of Natural History, in southwestern Pennsylvania, USA, 1986-2004. After identifying each captured individual to species and banding it with a uniquely numbered U. S. Bird Banding Laboratory band, we determined its sex using either plumage characteristics (for sexually dimorphic species) or the presence of a brood patch or cloacal protuberance. Adults were age-classified as either SY (second-year birds hatched the previous calendar year) or ASY (after-second-year birds hatched two or more calendar years ago), based on wing molt limits (Mulvihill 1993) and other plumage criteria that have since become standard in passerine a...,