On the adaptive value of intraclutch egg-size variation in birds.

Abstract

Used data from the field and the literature on 67 species of birds to analyze intraclutch variation in egg size, especially the deviation of the last egg from the clutch mean. Results support the view that intraclutch variation in egg size has an ultimate, adaptive value. Birds adopting the 'brood-reduction strategy' have a small final egg, particularly birds with large clutches, whereas birds adopting the 'brood-survival strategy' have a relatively large final egg, particularly birds with large clutches. -from Authors