A kittiwake is a kind of seabird. They nest on rocky ledges. To keep the nest free of excrement, the birds do not use the nest for a toilet, but go to the bathroom over the edge of the nest. This leaves conspicuous discoloration around the nest. Pieces of eggshell are also left in the nest after the young hatch. The white eggshell and discoloration make the nest area quite visible and easy to locate for predators like larger gulls and mammals.