Two morphs of ruff.

Two male ruffs co-occupy a single display court on a lek.

The dark male is an independent territory holder, while the white male is a nonterritorial satellite.

The independent male often tries to dominate the satellite by standing with its bill over the satellite's head.

The independent male benefits from having a satellite because females prefer to visit and mate on co-occupied courts, but pays the costs of sharing mating opportunities with the satellite.