Tern make up the clutch. Most species feed on fish caught by diving from flight, but the marsh terns are insect-eaters, and some large terns will supplement their diet with small land vertebrates. Many terns are long-distance migrants, and the Arctic tern may see more daylight in a year than any other animal. Terns are long-lived birds and are relatively free from natural predators and parasites; most species are declining in numbers due directly or indirectly to human activities, including habitat loss, pollution, disturbance, and predation by introduced mammals. The Chinese crested tern is in a critical situation and three other
Royal tern or it may cause it to drown if it is caught under water. Animals such as foxes, raccoon, and large gulls prey on tern chicks and tern eggs. Tern nesting sites can also be affected by the tides; if a tern colony has nested too close to the high tide mark a spring tide would flood the nesting site and kill the chicks and make unhatched eggs infertile. The royal tern is one of the species addressed in the "Agreement on the Conservation of African-Eurasian Migratory Water Birds" (AEWA). The AEWA covers 255 species that depend on wetlands for part