Herring gulls nest in colonies mainly on rocky cliffs but also on dunes and even on buildings in coastal towns or cities. A large nest of seaweeds and grass is built, sometimes as early as February. A single clutch of 2-4 eggs is laid but if these are lost more are laid. The eggs are laid on alternate days so that the young hatch at 2 day intervals. The eggs are incubated by both parents for 25-27 days.
The chicks, which are covered in grey down with dark blotches, are fed by both parents on regurgitated food. To obtain a meal they peck at the red spot on the parent's bill. Studies on the island of Skokholm, South Wales, have shown that herring gulls which feed their young on food scavenged from fish docks breed more successfully than those which mainly fish at sea.
At 42 days of age young herring gulls can fly and for the first year of their life their feathers are speckled brown. They do not develop the full adult plumage for several years.Read More: Herring Gull Habits