Biology

The breeding season begins in early May and nests are constructed upon cliffs; the clutch size is usually three eggs. Breeding success is relatively low but fledging generally occurs at around five weeks old (4). By mid-August, the young are independent and the annual migration to the wintering grounds can begin. These birds are relatively gregarious, roosting together in flocks usually during daylight hours (4). Foraging may also occur in groups, and flocks of around 25 birds have been seen feeding on the mud flats, their bills just skimming the surface of the water for food (4). A variety of tidal species are taken, from small fish to crabs and shrimp; foraging appears to take place in the dark or is dependent on the tide (4).