Antarctic tern

The Antarctic tern was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[3] Gmelin based his description on the "wreathed tern" that had been described in 1785 by the English ornithologist John Latham in his book A General Synopsis of Birds .

In non-breeding plumage, the black cap is reduced to just the area behind the eyes, the underparts become lighter and the bill becomes a dull reddish-black colour.

[11] Arctic terns also have shorter legs and more prominent black margins on the outside of their primary feathers.

[10] The Antarctic tern prefers rocky areas such as islets, with or without vegetation, often among other seabird species.

It usually nests on cliffs but is also found on rocky beaches, places inaccessible to cats or rats.

[2] This species has a large range, widely distributed around sub-Antarctic islands of the southern hemisphere and the Antarctic mainland.

[1] Recently, some populations have been found to take advantage of newly ice-free terrain on the north-eastern Antarctic Peninsula when nesting.

The Antarctic tern usually breeds from November to December, but this can vary depending on climate and the availability of food.

It can also be found nesting on the soil, sand, glacial moraines, or a vegetation mat, often within a small pit of pebbles or shells.

The female will lay one or two eggs per breeding season, which will be incubated by both parents for a period of 23 to 25 days.

Then, the chicks need to be fed by their parents for 27 to 32 days while they grow fully developed flight feathers.

[2] The larger water birds also prey upon the adults, leaving young chicks exposed to the harsh weather conditions and starvation.

The Antarctic tern will defend its nest against any intruders by repeated dive bombing, occasionally striking them with their sharp bill.

[10] The IUCN Red List classifies the Antarctic tern as a species of least concern in terms of conservation status.

[2] However, reproduction failures have been recorded on certain islands mostly due to introduced mammalian predators, namely domestic cats and rats.

Antarctic tern flying over St Andrews Bay, South Georgia, British Overseas Territories
Antarctic tern brooding on King George Island