A multifactorial study of variation in interclutch interval and annual reproductive success in the feral pigeon,Columba livia.

We examined the relative ability of multiple factors to explain variation in two interrelated life-history traits, interclutch interval and annual reproductive success, in feral pigeons. Seasonal influences, brood size, and female body mass and tarsus length explained significant amounts of variation in interclutch interval in this population, while female plumage phenotype was insignificant. These results are discussed in terms of resource allocation and responses to environmental heterogeneity. Multivariate selection analysis revealed strong directional fecundity selection on body mass, and correlated selection response on bill length. A prospective selection analysis based on estimates of the genetic variance-covariance matrix revealed that the mean change in a trait often differed in sign from the directional selection estimate. The relationship between annual reproductive success and these two traits was found only in melanic females, suggesting that selection differentials may covary with plumage pattern.