Data and code from: Re-assessing niche partitioning in MacArthur's Warblers: foraging behavior, morphology, and diet differentiation in a phylogenetic context

Due in large part to MacArthur’s classic 1958 paper, wood warblers in the family Parulidae are textbook exemplars of species competition and niche partitioning. The conventional wisdom suggests that subtle differences in foraging behavior are the principal means by which these nearly morphologically indistinguishable species are able to co-occur and avoid extinction. Yet, MacArthur’s study was in fact quite limited in scale, and he said little about the relevance of evolution to the study system. Here, we reassess MacArthur’s conclusions across an expanded set of syntopic warbler species in a forest in northern New York. We combine morphometrics, quantitative foraging data, and fecal metabarcoding—a direct measure of warbler diet—to study competition and niche partitioning in an evolutionary framework. We find close relationships between morphology and foraging behavior, but little connection between warbler ecomorphology and the 2,237 invertebrate taxa detected in their diets. Instead, diet remains phylogenetically conserved—closely related warblers eat similar suites of invertebrates, regardless of where they forage. Finally, we present evidence that these species not only partition niche space in the present day, but that competition has shaped their behaviors over evolutionary time. Here we provide the code and data associated with this project. Raw sequencing data can be accessed at the NCBI SRA under Bioproject PRJNA889412.