Infertile eggs: a reproductive cost to female dabbling ducks inhabiting unpredictable habitats

Abstract

For a female dabbling duck, the risk of being involved in forced copulations increases throughout the nesting season. This risk is greater for less territorial species occupying more unstable habitats. A potential consequence of forced copulations is that the female can be injured or killed. Species inhabiting the more unstable habitats lay more infertile eggs than those living in more stable habitats, perhaps because if females escape from pursuer males the egg will not be fertilised.