Much of our understanding of the reproductive physiology of birds is derived from research by poultry biologists. Starting in the 1970s behavioural ecologists began to explore the evolutionary consequences of female promiscuity across a range of taxa, but mainly insects and birds, focusing on the fact that, if females copulate with two or more males in a single reproductive cycle, selection will favour the male that fertilizes the female's ova. Since male-male competition and female choice ca...