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Arctic Tern | Sterna paradisaea
Noordse stern | Charrán ártico
The tern with the longest migration in the world, commuting between Arctic breeding grounds and the Antarctic seas. It touches the region mainly along the Atlantic coast: off Morocco and Western Sahara large numbers pass at sea in spring and autumn, usually far offshore. In the Mediterranean and the Middle East it is a rarity.
Voice
Higher and shorter than Common Tern: a sharp, rising kree-err and a rapid pee-pee-pee. Usually silent on migration.
Recording: Stanislas Wroza — CC BY-NC-SA 4.0 · shortened to the first 60 s, mono · xeno-canto
Identification
Slim and short-legged, with narrow wings and long tail streamers that project beyond the wingtips at rest. Breeding plumage: black cap, uniformly blood-red bill without a black tip, grey underparts with a narrow white cheek stripe. From above the wing is uniformly grey without a dark wedge; from below all the primaries are translucent, with a narrow, sharply defined black trailing edge. Autumn and young birds have a white forehead, black bill and a less obvious dark carpal bar than young Common Terns, with white secondaries.
Confusion species
Common Tern (Sterna hirundo) has an orange-red bill with a black tip, longer legs, a dark wedge in the outer primaries and only the inner primaries translucent from below. Roseate Tern (Sterna dougallii) is whiter, with a largely dark bill and very long white tail streamers. White-cheeked Tern (Sterna repressa) in the southeast is darker grey, with a grey rump and tail.
Habitat
On migration almost exclusively at sea and along the coast, often over the continental shelf where upwelling brings fish; rarely rests on beaches and sandbanks. Only exceptionally on lagoons or salt pans.
Where the bird is most at home, classified by the habitats of North Africa and the Middle East.
Range and movements
A regular and sometimes numerous migrant at sea off the Atlantic coast of Morocco and Western Sahara, in spring from April to early June and in autumn from August to October; from land, as at Cap Rhir and Dakhla, usually seen only in small numbers. Scarce in the Strait of Gibraltar and the western Mediterranean. Rare along the coasts of Algeria, Tunisia, Libya and Egypt. In Israel a rare migrant with a few records, mainly in spring at Eilat and on the Mediterranean coast. In Arabia a vagrant or very rare migrant, with a few records from Oman, the Emirates and Kuwait. Beyond the region it breeds right around the North Pole, south to Brittany and Massachusetts, and winters in the seas around Antarctica.
- Summer visitor (c. Apr–Sep)
- Passage (Mar–Apr, Oct–Nov)
- dark = core range, pale = thinly spread
How and when to look
The best chance is from a headland on Morocco's Atlantic coast in May or September, in a stiff westerly, or on a pelagic trip off Agadir or Dakhla. Compare every small grey tern with the many Common Terns: in good light the short legs and uniformly translucent hand are decisive.
Conservation status
Not globally threatened, but declining locally through food shortage around the colonies, linked to climate change and overfishing. In the region, bycatch and the state of the fishing grounds off West Africa matter most.
Scientific name
Sterna paradisaea | Pontoppidan, 1763
Pontoppidan described the species in 1763 and placed it straight away in the genus where it still stands. The genus Sterna was introduced in 1758 by Linnaeus. Sterna goes back to Old English stearn, which appears in the poem The Seafarer; the Frisians used a related word for terns. paradisaea is Late Latin for 'of paradise', from paradisus 'paradise'. The specimen the first description was based on came from Christiansø, Denmark.