Brighter Great Tit parents build bigger nests

摘要

Nest size is commonly believed to be naturally selected, and to covary with requirements of developing eggs and nestlings (Collias & Collias 1984). In many altricial bird species, it is an important component of parental effort, as parents devote an important amount of energy and time to nest building, but by doing so they expose themselves and their offspring to a substantial predation risk (Martin et al. 2000). In this paper, we studied nest-size variation in a Great Tit Parus major population in relation to breeding factors and parental carotenoid-based plumage characteristics. The Great Tit is a secondarycavity nesting species and females are solely responsible for building the nest (Gosler 1993). Sexual signalling via carotenoid-based plumage coloration is known to occur in this species (Hill & McGraw 2006). We found that plumage chroma of female and especially male Great Tits was positively related to nest size, suggesting greater female investment in nest building when mated to males in good condition.