Most species of seagull build their nests on the ground, while other species build their nests on elevated areas, such as cliffs or trees. Roofs may also be used for nesting. Seagulls build nests in colonies. Nests are constructed using twigs and other materials in the shape of a cup.
Seagulls are monogamous, although divorcing of pairs does occur. Seagulls often return to the same colony every year. Most species breed once a year, usually within the span of three to five months. The clutch size is generally three eggs. Both male and female seagulls take turns incubating eggs, with incubation lasting up to 26 days.