Common tern
The common tern is a seabird in the family Laridae. It has four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory, wintering in coastal tropical and subtropical regions.
About Common tern in brief
The common tern is a seabird in the family Laridae. It has four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. Breeding adults have light grey upperparts, white to very light grey underparts, a black cap, orange-red legs, and a narrow pointed bill. Depending on the subspecies, the bill may be mostly red with a black tip or all black. Its large population and huge breeding range mean that this species is classed as being of least concern, although numbers in North America have declined sharply in recent decades. The terns are small to medium-sized seabirds closely related to the gulls, skimmers and skuas. They are gull-like in appearance, but typically have a lighter build, long pointed wings, a deeply forked tail, slender legs and webbed feet. Most species are grey above and white below, and have aBlack cap which is reduced or flecked with white in the non-breeding season. Common terns may be infected by lice, parasitic worms, and mites, although blood parasites appear to be rare. Eggs and young are vulnerable to predation by mammals such as rats and American mink, and large birds including gulls,. owls and herons. Despite international legislation protecting the common Tern, in some areas populations are threatened by habitat loss, pollution or the disturbance of breeding colonies.
The nominate subspecies is 31 cm long, including a 6–9cm fork in the tail, a 77–98cm wingspan and weighs 110–141 cm. The common tern’s upperwings are pale as the summer, but the summer wears the black cap on the upperwings as the winter wears the pale grey on the summer. The bird feeds by plunge-diving for fish, either in the sea or in freshwater, but molluscs, crustaceans and other invertebrate prey may form a significant part of the diet in some Areas. It was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae under its current scientific name, Sterna hirundo. The word \”stearn\” was used in Old English and a similar word was used by the Frisians for tern in the poem The Seafarer, written around 1000 AD. Due to the difficulty in distinguishing the two species, all the informal common tern names are shared with the Arctic tern, which has a similar light build and long forked tails. This resemblance also leads to the informal name \”sea swallow\”, recorded from at least the seventeenth century. The Scots names picktarnie, tarrock and their many variants are also believed to be onomatopoeic, derived from the distinctive call. S. hirundo S. ipennis is sometimes considered to be between an intergrade between grade H and H.
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This page is based on the article Common tern published in Wikipedia (as of Nov. 07, 2020) and was automatically summarized using artificial intelligence.
