What kind of shelter does an arctic tern need?

Arctic terns do not construct shelters. They make scrape nests on open, elevated, and dry places such as cliffs, pebbly beaches, roof tops, and the ground. During the breeding season arctic terns are highly territorial and fiercely defend their scrape nests and chicks from predators such as glaucous gulls, glaucous-winged gulls, parasitic jaegers, long-tailed jaegers, skuas, and foxes.