Dissertation Research: Determinants of Annual Breeding Productivity of a Neotropical Migrant Bird, the Black-throated Blue Warbler

Dartmouth College, Hanover NH

Investigators

Abstract

Annual reproductive output has been shown to be a major factor affecting the recruitment, and hence the abundance, of Neotropical migrant birds. This study will identify and evaluate the mechanism(s) driving reproductive output that are critical to understanding current and future population trends of these species, many of which are declining. A review of the literature and analysis of breeding data on Black-throated Blue Warblers (Dendroica caerulescens) reveals that an important factor affecting the number of breeding attempts, and hence productivity, is territory level-food availability. This study will test to see if food is a causal factor using a food supplementation experiment. Additionally, observational data will be collected to test the alternative hypotheses that nest site availability, male assistance/protection, or female quality drives the number of breeding attempts and therefore annual reproductive output. This research contributes to current knowledge by examining population-level questions from the perspective of the individual female. Using a mechanistic approach, coupled with modeling this study will provide information necessary to assess how species respond to perturbations, which is especially import in light of proposed changes in species abundance due to global warming, habitat fragmentation, and other anthropogenic effects.