The Arctic tern tends to arrive back in its breeding habitats after the long migration from May to June (3). Males court females with a 'fish flight', an impressive aerial display which culminates in the male presenting the female with a 'gift' in the form of a fish (6). Nesting tends to occur in a hollow on the ground at a good distance from the shore in short vegetation (4) (6). Pairs, which mate for life, produce between one and three eggs, which are incubated for up to 24 days (3) (6). After a further 24 days or so, the chicks will have fully fledged. The males defend the nests if they are threatened, by diving at potential predators and livestock (6).
Arctic terns are very long-lived species, with a maximum recorded life-span of 29 years (3). This species feeds mainly on fish, particularly sand eels (3) (4), which they catch by making short dives into the water (6). Feeding tends to occur within three kilometres of the breeding colony, although they have been recorded to travel ten kilometres away in order to feed (4). When the breeding season is over, these birds head off once more on their long journey south (3).