Dietary niche breadth for Central European birds: correlations with species-specific traits

Abstract

Variation in dietary niche breadth among species is supposed to result from interactions within communities, but also from phylogenetic conservatism as well as constraints set by other traits. Here, we explore variation of dietary niche breadth across land birds occurring in Eastern Germany in correlation with phylogeny and traits like distributional range size, abundance, habitat range, body size, migratory behaviour and sexual dimorphism. First, we found a clear indication of phylogenetic conservatism: about half of the variation in dietary niche breadth across species was due to variation between families and genera. Habitat range, distributional range size of species in Eastern Germany and abundance did not correlate with dietary niche breadth. The significance of the correlation of dietary niche breadth with body size, distributional range size of species in Europe and plumage dichromatism depends on the details of the analyses. Nevertheless, even after controlling for phylogeny, we found robust correlations of dietary niche breadth versus migratory behaviour as well as sexual size dimorphism: species with a narrow dietary niche tend to be migratory and, in species with a broad dietary niche, males tend to be larger than females.