Reproductive outcomes determine the timing of arrival and settlement of a single-brooded Nearctic–Neotropical migrant songbird (Catharus fuscescens) in South America

Abstract

ABSTRACT The breeding seasons of Nearctic–Neotropical migratory songbirds are thought to be constrained by the temporal demands of subsequent seasons. In any population, a subset of adults may fail to fledge young despite repeated attempts, which may prolong reproductive effort. We used geolocators to track the single-brooded Veery (Catharus fuscescens) from a Delaware, USA, breeding site to South America and back, to examine how reproductive failure and the timing of reproduction affected the spatiotemporal aspects of the nonbreeding season. We also considered the effect of additional variables: age, sex, time in population (i.e. experience), productivity, and nutrition via ptilochronology. We found that clutch completion date and reproductive success were significant predictors of South American entry and arrival date at first winter sites, respectively. Reproductive success also influenced the latitude of winter sites. For females only, there was a consequence of reproductive failure: unsuccessful fema...