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
Tern tern subspecies are endangered, including the California least tern and the Easter Island race of the grey noddy. Most tern species are declining in numbers due to the loss or disturbance of breeding habitat, pollution and increased predation. Gull populations have increased over the last century because of reduced persecution and the availability of food from human activities, and terns have been forced out of many traditional nesting areas by the larger birds. A few species are defying the trend and showing local increases, including the Arctic tern in Scandinavia, Forster's tern around the Great Lakes, the Sandwich tern in