Nests are also preyed on by gulls, magpies, ravens, crows, owls, and grackles. Three to four pale bluish-green eggs are laid. Both parents take turns incubating for 20-26 days. The mostly bare pink skin of the altricial chicks is sparsely covered with fine dark down. Their short flesh-colored bills are marked by three indistinct black bands.
Parents feed the begging chicks by dribbling regurgitated food into their upturned bills.
The last chicks to hatch are usually outcompeted by older siblings and are likely to starve. The chicks develop rapidly and by nine or ten days of age are able to wander a short distance from the nest. The first few weeks are spent hiding in vegetation near the nest, but by the end of week three they are actively exploring the immediate area. They make their first flight attempts with short glides at four weeks. They begin to take short flights from the colony at six to seven weeks of age and are believed to be totally independent by eight weeks old.