A Co-occupied ruff court

A co-occupied ruff court

The photograph depicts a resident (territorial) male (the bird on the far left) and a visting satellite male. Residents recruit satellite males to their courts, apparently to make the court more attractive to females. Recent evidence shows the plumage polymorphism, which maps closely to the behavioural polymorphism (residents versus satellites) to be controlled by a relatively simple single-locus Mendelian system.