Tern

Terns are seabirds in the family Laridae that have a worldwide distribution. They are slender, lightly built birds with long, forked tails, narrow wings, long bills, and relatively short legs. The Chinese crested tern is in a critical situation and three other species are classed as endangered.

About Tern in brief

Terns are seabirds in the family Laridae that have a worldwide distribution. They are slender, lightly built birds with long, forked tails, narrow wings, long bills, and relatively short legs. Most species are pale grey above and white below, with a contrasting black cap to the head. The sexes are identical in appearance, but young birds are readily distinguishable from adults. Terns have a non-breeding plumage, which usually involves a white forehead and much-reduced black cap. The Chinese crested tern is in a critical situation and three other species are classed as endangered. International agreements provide a measure of protection, but adults and eggs of some species are still used for food in the tropics. The eggs of two species are eaten in the West Indies because they are believed to have aphrodisiac properties. The word tern was used for these birds in Old English as early as the eighth century. Some authorities consider the inland black tern as well as the marine tern species to be similar to the Seafarer, written in the ninth century or earlier, although the older form of the word lingered on in Norfolk dialect for several centuries. Some older forms of the term tern can be traced back to the 11th century, when it was used to refer to a group of wading birds known as ‘tearants’ The word ‘seafarer’ can also be found in the eleventh century, although it is not as widely used as it was in the early 20th century.

The Arctic tern may see more daylight in a year than any other animal. The 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. Within the order Charadriiformes, the terns form a lineage with the gulls, and, less closely, with the skimmers, skuas, and auks. Behaviour and morphology suggest that the Terns are more closely related to the gullS than to the skuers orskuas. For many years they were considered to be a subfamily, Sterninae, of the gull family, Laridae. In 1959, only the noddies and the Inca tern were excluded from Sterna. A recent analysis of DNA sequences supported the splitting of Sterna into several smaller genera. One study of the cytochrome b gene sequence found a close relationship between terns and a group. of waders in the suborder Thinocori. These results have been interpreted as showing either a large degree of molecular convergent evolution between the tern and these waders, or the retention of an ancient genotype. As now, the term ‘stearn’ is used for several species of terns, including the inlandblack tern.

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