Tern caugek

The Sterne caugek ( Sterna sandvicensis ) is a species of marine birds of the family of the Laridés. One gives him also the yelling name of plovre, privaret (or puveret), tavernot. Phylogenic research recent resulted in gathering within the kind Sterna the majority of the terns of which this species placed sometimes before in the kind Thalasseus .

The " term; caugek" is a reference to the cry of this bird; sandvicensis is the Latinized name of a city of the Kent, Sandwich (cf the Swedish name: Tern of Kent)

Among the terns attending the European coasts, she recognizes herself with the yellow point of her nozzle.

Systematic position

The family of the sternidés was included in that of laridés of which it constitutes a tribe, the Sternini S.
Elle is still sometimes called Thalasseus sandvicensis , but the 6 species of the kind Thalasseus Boie 1822 were integrated into the kind Sterna following the results of the tests of Hybridation of the DNA.

This species is very close to the elegant Sterne ( Sterna elegans ), to the Sterne of the East ( Sterna bernsteini ) and especially to the voyageuse Sterne ( Sterna bengalensis ) with which one could observe hybridizations.

Subspecies

There exist three subspecies of Sterna sandvicensis :

Sterna sandvicensis sandvicensis which niche on the Atlantic and Mediterranean coasts of the Europe until the Black Sea and the Caspian Sea, and winters on the African continent (especially in the west) and in the Arabic Péninsule.
Sterna sandvicensis acuflavida which niche on the Atlantic coasts of the North America, and winters in the the Caribbean and in South America.
Sterna sandvicensis eurygnatha (sometimes regarded as a species with share: Tern of Cayenne) which niche on the Atlantic coasts of South America and can mix, in the north of its surface of distribution, with S.S. acuflavida .

Morphology

Size: 36 to 43 cm
Weight: 210 to 260 G
Scale: 85 to 110 cm

The Tern caugek has the ashed gray back very pale, the neck and the belly white. Its nozzle, length and pointed, are black with the yellow point (it can be yellow or orange at the South American subspecies). Its legs are black. It presents on the head a entirely black Calotte during the season of reproduction, but of which the frontal part becomes white as of July, and prolonged by short crested a erectile always sinks. Its tail is white, rather short, a little fourchue.

In this active and noisy bird, the cry is unmatched and criaillor, especially emitted during the flight - kerrièk-kerrièk-. During the bridal parade, it emits gutturaux cries, nozzle pointed to the top - krak-krak-

Behavior

Social behavior

This tern, very Gregarious, lives in dense colonies with very brought closer nests, sometimes with less than 30 cm from/to each other (one can count up to 5 to 6 nests with the m ²). A colony of tern caugek can count several thousands of birds. Contrary to other species of terns, it is hardly aggressive towards the predatory potentials. It counts on the density of the nests to decrease the risks of predation on its small. The Tern caugek niche sometimes near more aggressive species (Arctic tern, Black-headed gull) to discourage the predatory ones.
Les colonies is generally installed on the maritime coasts, but one can meet them near coastal lakes.

Flight

Description of the flight

Thanks to its long bent wings, the Tern caugek is an excellent sailing ship, capable of abrupt direction and shiftings of speed.
Pour to locate its preys, it practices a stationary beaten flight (flight in " saint esprit"), the nozzle directed downwards. Once the located prey, the tern folds up its wings and plunges, in oblique or with the vertical, sometimes an important height. Its rate of success is very high.

Migration

The Tern caugek is a migrating species which joined its surface of nesting in north about April/May, then sets out again towards the south, towards its zone of wintering from July to September. The migration is sometimes very long: the terns caugek of the north of Europe can go to as winter far as the Mozambique, having skirted with this intention all the west coasts and south of Europe and Africa, then after having circumvented the Cape of Good Hope, re-installed part of the Eastern African coast.

Food

The Tern caugek nourishes fish almost exclusively. Lançon S, Sardine S, Anchovy, Herring S, Sprat S and other small marine fish constitutes 98% of its food mode. It can also fish marine worms or molluscs.

Reproduction

The terns caugek, which can live up to 24 years, reach their sexual maturity at 4 years.
La season of reproduction generally takes place in May - June. The bridal parade presents a phase of lifting flights accompanied by many cries, with great rises followed by fast descents. The phase on the ground consists of a circular dance of the two partners, half-opened nozzles, as well as a succession of particular cries, nozzles in the air. The male presents in offering a small fish to the female.
Après the coupling, the parents make a hole in the ground as a nest. The female often lays, with same the ground, one to three eggs of variable color, energy of the white to light chestnut, often decorated with small darker spots.
L' incubation (which lasts from 22 to 26 days) and the nourrissage of small are ensured by the two parents. The chicks are Nidifuge S and can venture out of the nest a few hours after their birth. The chicks of a fifteen or so days gather as a pouponnière supervised by adults. The small ones become able to fly after five weeks.

Distribution and habitat

The Tern caugek is an migratory bird, its distribution thus varies according to the seasons. The nesting is done primarily on the European coasts or the Atlantic coasts of the American continent (see the detail of the subspecies here).
Le departure towards the zones of wintering at the end of September takes place, and the return towards the zones of nesting at the end of March.
Cet bird niche preferably on low, stony or sandy coasts, with close-cropped vegetation or goes away.

In France, the principal colony of terns caugeks is on the Natural reserve of the bench of Arguin, with an average of 4000 couples.

Statute and safeguarding

She is mainly threatened by the modification of her habitat, the disturbances and the predation by the foxes at the time of the nesting, and the reduction in the resources of fishing. It is a protected space by the European commission, which estimates its population at: 65000 couples, for the above mentioned reasons.
L' US Migratory Bird Act classifies also this tern among the species to be protected.
L' Agreement on the conservation of the migrating water birds of Africa-Eurasia class of category B2a (population rather many but considered as requiring a special attention because of a concentration on a small number of sites at an unspecified stage of their annual cycle) Asian, Western-European and West African populations of terns caugeks, and of category A3a and A3c (population very few considered as threatened because of a concentration on a small number of sites at an unspecified stage of their annual cycle and of a demonstration of a significant decline in the long run) those of the Mediterranean and Black Sea.
Birdlife International estimates that the European population includes/understands from 82 to 130 thousand couples in summer (what represents, according to Birdlife International, 50% of the total population), and 3.200 wintering individuals (Russia included). This population having recorded a decline certainly moderated, but generalized with all the countries, this organization classifies this bird in category SPEC2 (unfavourable situation in Europe, species concentrated in Europe)

IUCN class this species in the " category; concern mineure" , estimating its world population at a variable number between: 460000 and: 500000 individuals, on a surface of distribution extending on: 100000 to 1 million km ².

Curiosities

Several countries emitted a stamp with the effigy of this bird: the Holland (1982), the Gambia (1999), the Albania (1973) and islands of Jersey (1998), of Aurigny (2003) and of Aruba (2004).

See too

External references

External bonds

IUCN 2006
birdguides

Photographs and vidéos

Gallery aves on the tern caugek
Gallery photo Flickr on Avibase
photo Gallery on African Bird Club
Video IBC (Internet Bird Collection) video of a colony of terns caugek on the Delta of Ebre
Video IBC (Internet Bird Collection) bridal Parade and coupling, Delta of Ebre.
Birds off the world one posting stamps

Bibliography and texts

Estimate of the European population by International Birdlife
Cabard P. and Chauvet B. (2003) Etymology of the names of birds . Belin. ISBN 2-70113-783-7
Stastny (1989) Water birds . Gründ, Paris. ISBN 2-7000-1816-8
Hume R., Lesaffre G. and Duquet Mr. (2004) Birds of France and Europe . Larousse. ISBN 2-03-560311-0
Stienen E.W.M. (2006) Living room with gulls: trading off food and predation in the Sandwich Tern . ISBN 90-367-2480-5 http://dissertations.ub.rug.nl/FILES/faculties/science/2006/e.w.m.stienen/DissertatieE.W.M.Stienen.pdf

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