Olrog’s gull nests in colonies of between 12 and 400 pairs, mating from September. Nests vary from a simple scrape lined with vegetation to raised platforms of twigs and plants, in amongst glasswort (Salicornia spp.) and grass tussocks. They are often far from the high tide line and can be very tightly packed together. Females lay between two and three eggs, and once the young have fledged the population disperses from the breeding site (5).
Touring the shoreline and swimming among reeds in the shallows, Olrog’s gull feeds mainly on crabs and mussels as well as fish and offal. It may also hover over the surface of the water and drop onto passing prey (5).