The European Shag nests in colonies on rocky, wave-exposed skerries and islands. The nest is placed on a rock ledge, in a fissure or among boulders and is built from seaweed, twigs and other plant material. The female normally lays 2–4 eggs, and both parents share in the incubation, which lasts about a month. The young are fed in the nest for several weeks before they are ready to fledge.