No evidence for trade-off between egg dimensions and clutch size in first, second and third clutches of the Tree Sparrow Passer montanus

Abstract

The trade-off between egg dimensions and clutch size is an important factor in life-history theory. Compromise between egg size and clutch size has been demonstrated in many species with negative, positive and non-significant correlations. The aim of the present study was to examine the relationship between egg dimensions (length, breadth, volume) and clutch size in a Croatian population of the Tree Sparrow Passer montanus for their first, second and third clutches in 2019. Neither negative nor positive associations were found between clutch size and egg dimensions in this study. Results do not support predictions based on the hypothesis of compromise between egg size (egg dimensions) and the number of eggs laid per nest (optimal clutch size/egg size).