Arctic Tern - Sterna paradisaea - 1, Ny Alesund, Svalbard

Arctic Terns, Sterna paradisaea at Ny Alesund, Svalbard. This picture was taken near to the nesting grounds, the birds dislike anything approaching their nests or looking like it might approach their nest and this seems to include each other even when the bird in question occupies the adjacent nest, so aerial squabbling is common.

Arctic Terns are not especially large birds, they have a length of 33-39cm (13-15") and wingspan of 76-85cm (26-30"), they weigh just 86-127g (3-4.5 oz). They are famous for their annual migration which takes them from Northern to Southern polar regions and back again every year. For some individuals, this is as much as 80,000km per year. They travel more than any other animal on earth and see more daylight than any animal being in each polar region during its respective summer with 24 or near 24 hour daylight. In a lifespan of 30 years or more, an Arctic Tern may travel more than 2.4 million km.

The distribution of the Arctic Tern. Breeding range in red, migration green arrows and northern hemisphere winter is spent in the blue area around Antarctica.

Picture credit - Andreas Trepe, licensed under creative commons attribution-share alike 2.5 generic license.