PROTECTION / THREATS / STATUS:
The Roseate Tern is widespread but remains very local on the coasts of six continents.
This species is affected by trapping of adults and egg collecting in E Africa and the Caribbean, but also in some wintering areas. But increase of long-line activity and predation also have a significant impact. In N Europe, habitat loss has caused the extinction of some colonies.
The global population is estimated to number 200,000/220,000 individuals. The overall trend is uncertain with decreasing, increasing and stable populations depending on the range.
The Roseate Tern is not considered globally threatened, and the species is currently evaluated as Least Concern.
Fr: Sterne de Dougall
Ang: Roseate Tern
All: Rosenseeschwalbe
Esp: Charrán Rosado
Ita: Sterna di Dougall
Nd: Dougalls Stern
Sd: rosentärna
Photographers:
John Anderson
John Anderson Photo Galleries
Aurélien Audevard
OUESSANT DIGISCOPING
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD Vol 3 by Josep del Hoyo-Andrew Elliott-Jordi Sargatal - Lynx Edicions - ISBN: 8487334202
OISEAUX DE MER – Guide d’identification de Peter Harrison – Editions Broquet (Canada) – ISBN-10 : 2890004090 – ISBN-13 : 978-2890004092
Terns of Europe and North America Par Hans Larsson, Klaus Malling Olsen – Editeur: A&C Black, 2010 – ISBN: 1408131684, 9781408131688 – 224 pages
Road to recovery for the Roseate Tern
Protecting the rarest breeding seabird in Europe
Roseate Tern breeding dispersal and fidelity: responses to two newly restored colony sites
American Bird Conservancy
speciesatrisk.ca
What Bird-The ultimate Bird Guide (Mitchell Waite)
Wikipedia, the free encyclopaedia
Roseate Tern
Sterna dougallii
Charadriiformes Order – Laridae Family
INTRODUCTION:
The Roseate Tern is present on the coasts of six continents where it is widespread although very local.
This species breeds on islands with dense vegetation in temperate regions, whereas it prefers barren islets in tropics. It forages in estuaries and offshore. During the non-breeding season, they often roost on sandbars or beaches at river mouths, in estuaries or the ocean front. They breed in colonies where they lay the eggs in a scrape on the ground. Both adults share the nesting duties.
The Roseate Tern is still trapped in some regions, and the species is affected by the increase of long-line activity, also by predation and habitat loss depending on the range.
The population trend is uncertain with some decreasing populations while others are stable or increasing. The species is not considered globally threatened for the moment.
The name of this tern pays tribute to the Scottish physician and collector Dr Peter McDougall (1777-1817).
The word “roseate” refers to the pink wash on the breast in breeding plumage.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 33-41 cm (including 13-22 cm of outer rectrices)
Wingspan: 72-80 cm
Weight: 95-130 g
The Roseate Tern in breeding plumage has white body and black cap, with black extending down the nape. Mantle and wings are pale grey. On the upperwing, the outer primaries appear mostly blackish. The tail is strongly forked and shows long, white streamers.
The underparts are white with pale creamy-pink wash on the breast at the beginning of the breeding season. This pinkish tinge is difficult to see in bright sunlight. It usually becomes worn during the incubation, usually concealed by the white tips of the feathers.
In the early breeding season, the bill is black but the colour varies geographically and in some populations, the terns develop some red at base, late in incubation. A third or half of the bill turns red when the chicks fledge, and the bill becomes black again in August/September.
The eyes are blackish brown. Legs and webbed feet are bright orange-red in breeding adults, but they are dark brownish during the rest of the year.
The adult in non-breeding plumage has shorter tail. On the head, the forehead is white and the black is restricted to the back of the head. Legs and feet are black.
Male and female have similar plumage, but the female is slightly smaller than male.
The juvenile has the mantle barred with black or brown crescents, whereas back and rump are mottled brownish grey.
Bill, legs and feet are blackish.
The subadult resembles non-breeding adult, but it has white forehead and hindneck with brownish speckles. We can see a brownish mark across the crown, extending to ear-coverts and nape.
SUBSPECIES AND RANGE:
The Roseate Tern has a worldwide distribution and can be found from Europe to Africa and to Australia. The smallest birds occur in Australia, and the largest in the North Atlantic.
The Roseate Tern has three subspecies:
S.d. dougallii (described above) is found from Nova Scotia to New York and Florida, S through Gulf of Honduras and West Indies to islands off N Venezuela. It breeds in Mexico and also Azores, NW Europe, E and S Africa from S Somalia to Tanzania, and in W and E Cape Province.
The American populations winter in the Caribbean and along the north eastern coasts of South America.
S.d. gracilis is found from Seychelles S to Madagascar and E to Rodrigues Island. It also occurs in Arabian Sea, W and SE India, Sri Lanka, Andaman Islands, Mergui Archipelago and Cocos Islands. Also Ryukyu Islands in Japan, coastal China and Taiwan S to Greater Sundas, Moluccas and Australia, and E to S New Guinea, Solomons, New Caledonia (and possibly Fiji, E to Tuamotu islands).
This race has more extensive red on the bill during the breeding season, and the body is smaller.
S.d. korustes is found in Sri Lanka, Andaman Islands and Mergui Archipelago.
This race has darker grey mantle than S.d. gracilis, and the bill is shorter.
HABITAT:
The Roseate Tern nests on rocky, coral and sandy islands with some low vegetation. They breed near shallow waters where they forage, often in protected bays and estuaries. They usually forage in coastal waters, although sometimes, they can be seen well offshore, especially in warmer waters.
In tropics, they usually prefer barren islets.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Roseate Tern’s most common calls are a clipped, high-pitched “keek” and a lower “kir-ik”.
When alarmed at the colonies, the terns produce a lower, harsher series of “aaach” or “kraak” calls on a single pitch. This call is given while mobbing an intruder near the nest or other predator in the water.
Another alarm call, a “kiu” note, is given when an intruder is approaching the nest. The tern also gives a louder “kyeep”.
In flight, the Roseate Tern gives a sharp “keek” while foraging in flock.
But this species has several different calls, depending on the situation.
BEHAVIOUR IN THE WILD:
The Roseate Tern feeds primarily on fish, and mainly small fish such as sand lance and herring off the coasts of eastern North America. But it also takes some molluscs and crustaceans. Other fish species include bluefish, Atlantic mackerel, Atlantic silverside and anchovies.
It catches prey by plunge-diving from heights of 1-6 metres, sometimes up to 10-12 metres. It may submerge under the surface. It forages mainly by patrolling in flight above the sea, but it hovers less than most tern species. The prey is caught with the bill and brought to the surface. The fish is swallowed head first or the tern carries a single fish crosswise back to the colony to feed the chicks.
Depending on the range, the tern may also feed by contact-dipping. They feed sometimes over foraging flocks of Phalacrocoracidae, Gaviidae and Alcidae species, they also follow the fishing boats and steal fish from other seabirds.
The Roseate Tern is monogamous with long-term pair bond. They nest colonially on small islands, often with other tern species such as the Common Tern.
They perform beautiful aerial displays with a fast ascent with rapid, jerky wingbeats, from 30 to 300 metres height. At the highest point, the male starts to glide down with the bill pointed downwards. The female glides close over the male with the neck stretched and twisted sideways. Then, both birds glide down together while the female is swaying from side to side close above and ahead of the male.
But they also display on the ground with the tail raised and the neck arched. The male may also feed the female. Both adults share the nesting duties.
The Roseate Tern is a long-distance migrant. The north eastern birds migrate S in late August/early September, from the US in the NE to the waters off Trinidad and N South America, and along N and E coasts of South America to E Brazil.
In the Old World, the E African birds are absent between November and May, and probably move to South Africa.
Numerous non-breeders can be found in Australia, S Great Barrier Reef. From recaptures of marked birds, these terns belong to the Asian population, and some of them to local population, but both are the race S.d. gracilis. This is the evidence that the Asian breeding birds of this species spend the winter in S Hemisphere.
Like other terns, and generally seabirds, the Roseate Tern is very agile in flight. The flight is active and graceful, especially during the courtship displays. The wingbeats are fairly stiff, quick and almost hurried.
REPRODUCTION OF THIS SPECIES:
The breeding season occurs in April in W Australia, India, Sri Lanka and Madagascar, May-June in NE USA and Europe, June in Somalia, July-August in Kenya and Seychelles, and June-October in South Africa. The laying may occur earlier in periods of food abundance.
The Roseate Tern usually breeds in mixed colonies, often with the Common Tern, but large monospecific colonies also exist. They are very dense, with nests 40 centimetres apart.
The nest-site is on the ground, often under vegetal cover such as grass or shrubs, also on rock ledge or open bare sand. The nest is a shallow scrape made by both adults. It is often lined with some debris.
The female usually lays 1, 2 or sometimes 3 cream to pale olive eggs with dark markings. Both adults incubate, but mainly the female, during 22-26 days.
At hatching, the chicks are mottled dark. The underparts are buffy white with dark grey chin and throat. They are fed by both parents. They usually leave the nest very soon and hide in the surrounding vegetation until they fledge, at 23-30 days of age, when they perform their first flight. They remain within the family group for two months at least.
