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Lesser crested tern | Thalasseus bengalensis
Bengaalse stern | Charrán bengalí
The lesser crested tern is the one orange-billed crested tern that breeds in the Mediterranean, and it does so on a few sandy islets off the coast of Libya. Birds from there reach Spain, where the same individuals turn up on the same salt pans year after year.
Voice
A shrill, grating krik or kerrick, higher and sharper than sandwich tern and held for less time. Around the colony it becomes a continuous rasping chatter that carries over the water. In Spain that is often how the bird gives itself away: one call pitched too high, coming out of a party of sandwich terns moving along the surf line.
No freely licensed recording is available for this species yet.
Identification
A medium-sized tern, slimmer and lighter than greater crested and a little smaller than sandwich tern. The bill is the feature that carries: straight, fairly slender and clean orange, without a dark tip. In breeding plumage the black cap runs forward to the bill base and ends behind in a short shaggy crest; from June the forehead whitens and the bird keeps a black, white-flecked rear crown. Mantle and upperwing are pale grey, and rump and tail share that grey, so there is no white block at the rear end. The legs are black, the underparts white. Juveniles are scaly above with a dark wing bar and a duller, more yellow-orange bill. Mediterranean birds belong to emigratus, the palest form of the species.
Confusion species
In Spain sandwich tern is the yardstick every lesser crested has to be measured against, and the bill settles it: clean orange along its whole length against black with a yellow tip. If the head disappears behind a swell, look at the rump — grey and blending into the back on lesser crested, white and contrasting with the mantle on sandwich. Lesser crested is also smaller and more compact, with a shorter crest and a finer head. Elegant tern is the harder call, since it too has an orange bill: that bill is longer, thinner and droops towards a yellower tip, the crest is markedly longer, and in winter plumage the eye of an elegant tern stays inside the black while a lesser crested's eye sits out in the white. Greater crested tern, finally, is bigger and far darker on the mantle, with a yellow bill and a white forehead at all seasons.
Habitat
Low, bare sand and coral islets for nesting, and shallow inshore seas, lagoons, salt pans and fishing harbours for feeding and loafing. It plunge-dives for small shoaling fish, often just beyond the breakers and along tide lines at river mouths. Outside the breeding season it follows the coastline and rarely goes far offshore.
Where the bird is most at home, classified with EUNIS — the European standard for habitats.
Range and movements
The world population is large, running from the Red Sea and the Gulf to South-East Asia and Australia, but inside this guide's map it comes down to one small separate stronghold: fewer than 2,400 pairs on islets off the Libyan coast, centred on the Gara islands near Benghazi. Scattered breeding records come from Italy, Spain, Greece and France, usually a single bird inside a sandwich tern colony and often in a mixed pair. In Spain it is an annual visitor in small numbers, with the salt pans of Santa Pola and Torrevieja, the Chafarinas islands and the Strait of Gibraltar as regular sites, and some birds return to the same stretch of coast for years. Mediterranean breeders winter along the Atlantic coast of West Africa. At the eastern edge of the region the species appears at Eilat and along the Israeli coast, those birds coming from the Red Sea.
- Breeding (summer)
- Winter
- Passage
- Migration direction
- dark = core range, pale = thinly spread
Where and when to look
In Spain the salt pans of Santa Pola and Torrevieja are the best bet: work through the roosting terns on the dykes in July and August and look for the orange bill among the black ones. On the open coast the job is different — count through the passing parties of sandwich terns and trust the call. Always photograph the spread wing and the rump as well as the head, because a single head shot rarely convinces a records committee.
Conservation status
Not globally threatened, but the Mediterranean population is small and squeezed onto a handful of islets, which leaves it exposed. Egg collecting, disturbance by fishermen, dogs and rats on the breeding islands, and the use of explosives in fishing are the heaviest pressures, with a changing climate and declining small fish stocks on top. The birds are covered by the Barcelona Convention and by the African-Eurasian Waterbird Agreement.