Variance in clutch size

Summary Most studies of the evolution of clutch size have concentrated on changes in the mean and have neglected the variance of clutch size. We suggest that the variance is very important and discuss how it might be fruitfully analyzed.Acknowledgment. I thank the Royal Australasian Ornithologists Union and the North American Nest Record Card Program for access to records of shorebird reproductive performance and Dr P. A. Baghurst for considerable assistance.