After today, the staged murre colony will be complete. Hundreds of birds crowd onto a cliff face. The male throws his head back, pointing his bill up in the air. Both sexes bow at each other, stroke each other's bills and preen each other. They build no nests, but unceremoniously lay their eggs wherever there is a bare patch of ledge.
Birds pile on top of each other as they incubate the eggs.
These crowded conditions would seem to pose certain problems for the birds. Murre eggs are mottled with pigments laid down as the egg passes through the mother's birth canal. The eggshell pattern is distinctive, and both parents learn to recognize the egg shortly after it is laid. Similarly, they learn to recognize the chick once it hatches, so they can be sure to tend to their own progeny. Even though each bird's kazoo-like call sounds the same to human ears, murres distinguish each other's vocalizations.