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
Forster's tern Europe and has occasionally wintered in Great Britain and Ireland. Forster's tern is often found in marshes over shallow open water. It is a shallow plunge-diver that often hovers before attacking. When hunting, its head is pointed downward whereas when travelling, it is pointed forward. It is a colonial nesting species that builds a shallow nest using marsh vegetation and often competes with gulls for nesting sites. A breeding colony may vary in numbers from a few couples to a thousand individuals. In many occasions, Forster's tern will share nesting sites with the Yellow-headed blackbird. Both parents are involved in