Arctic Tern

What does a Arctic Tern look like?

Arctic terns are medium-sized birds, with a general appearance of whitish-grey plumage and a jet-black cap. Their scapulae are fringed brown, with some tipped white. Upper wing is grey with a white leading edge. They have grey outer webs on their deeply forked, whitish tail, which ends in elegant tail streamers that can reach a length of 11.5cm. Their white flight feathers appear translucent from below. In summer, adults are pale blue-grey above and white below, but with a dusky grey wash on breast and belly. The arctic terns’ legs and feet are coral-red in summer, and darker in winter. During breeding season, their long, distinctive blood red bill loses it black tip. The most obvious difference between adults and juveniles is that young birds have black legs and bill and not the red colouring of the adults. During their first summer their caps are smaller, with more white on the crown. They have a white forehead, and their plumage is pale grey above. Juveniles also have a distinctive dark bar on leading edge of their wings. Arctic terns spend most of their lives in the air, so their legs are short and relatively weak.

Arctic Tern on a post

Arctic Tern on a post

What does a Arctic Tern sound like?

Arctic tern colonies are very noisy, and will be filled with the birds’ shrill, nasal, grating notes, and short, sharp alarm call.

Arctic Tern call

Peter Stronach, XC597548. Accessible at www.xeno-canto.org/597548.

Did you know?

Arctic terns are also known as ‘sea swallows’ due to their tail streamers and flight silhouette.

What does a Arctic Tern eat?

Arctic terns eat marine fish, crustaceans and occasionally insects.

Arctic Tern with fish

Arctic Tern with fish

Where can I see Arctic Terns?

Arctic tern colonies are mainly confined to coasts, where grassy islands are favoured. In the UK, the best place to see them is the Farne Islands in Northumberland or on the Northern Isles. They begin to arrive back from the Antarctic in late April to May, sometimes passing inland through central England. During this spring passage they can be found at inland reservoirs. During the autumn, as they head south after breeding, look out for them around the coast.

Arctic Tern

Signs and spotting tips

Arctic terns can be difficult to separate from the common tern, but they have a shorter bill and head. Their flight is often more elastic and gracefully bouncing than the common tern’s. The arctic tern often dives with a stepped hover, dropping short distances and hovering again before taking the final plunge; at times they will snatch prey from the surface of the water. They have a distinctive forked tail with tail streamers.

How does a Arctic Tern breed?

Arctic terns breed on lakes, rivers and tundra and generally return to the same colony each year. Arctic terns mate for life. Their relationship begins with an elaborate courtship ritual wherein the female will chase the male high into the sky and the slowly descend. This is followed by a ‘fish flight’ in which the male will offer fish to the female. The arctic tern’s nest is shallow, unlined scrape. The female will lay a clutch of 2-3 eggs which are pale buff, variously spotted and scrawled with a dark brown camouflage. Eggs are incubated for 20-27 days. Once hatched, chicks are brooded by the adults for the first ten days. Adults will raise one brood a year. The birds reach sexual maturity at 4 years of age.

Arctic tern nest

Arctic Tern nest

Juvenile arctic terns

Juvenile Arctic Terns

How long does an Arctic Tern live for?

They typically live for 20 years. Studies show more than half of the species will live past their 30th birthday,

Do Arctic Terns migrate?

Arctic terns are perhaps the epitome of migrating birds. They are a circumpolar species and each year travel from pole to pole to take advantage of a double summer. Populations winter in the Antarctic and then travel back 12,000 miles, at a minimum. Average migrations are around 30,000 miles. One bird was recorded as flying 57,000 miles in the course of migrating to and foraging in Antarctica. In the UK, the arctic tern is a summer visitor, arriving from the end of April until October.

Did you know?

The arctic tern has the longest migration of all birds.

Threats and conservation

There are currently estimated to be 53,000 breeding pairs of arctic terns in the UK, where they have an Amber conservation status. Due to the species’ dependence on a healthy marine environment, it has been affected by a decline in fish stocks.

Country distribution of a Arctic Tern

Other birds in the Gulls and terns family