The snowy-crowned tern (''Sterna trudeaui''), also known as Trudeau's tern, is a species of tern in the family Laridae. It is found in Argentina, south-east Brazil, Chile, Paraguay and Uruguay, and as a

vagrant Vagrancy is the condition of homelessness without regular employment or income. Vagrants (also known as bums, vagabonds, rogues, tramps or drifters) usually live in poverty and support themselves by begging, scavenging, petty theft, temporar ...

in the Falkland Islands. The tern's natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s are

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s, shallow

sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ...

s, and intertidal

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es. The species was first described by the American ornithologist

John James Audubon John James Audubon (born Jean-Jacques Rabin; April 26, 1785 – January 27, 1851) was an American self-trained artist, naturalist, and ornithologist. His combined interests in art and ornithology turned into a plan to make a complete pictoria ...

in 1838. He had been sent a specimen by his friend Dr James de Berty Trudeau (1817–1887) of Louisiana, who had found several of the terns at Great Egg Harbor Bay, New Jersey. Audubon named the bird in his honour.

Description

The adult snowy-crowned tern has a moderate-sized head and a slender body. It reaches a length of about . The bill is slender, flattened, slightly down-curved and about the same length as the head. It is black with a yellow tip, a yellow edging to the mandibles and a yellow base to the lower mandible. The iris is brown. Around and behind the eye is a slatey-grey patch, the rest of the head being white. The upper-parts and underparts are light bluish-grey, apart from the axilliaries, rump and tail-coverts, which are white. The wings are long, slender and pointed, sometimes with a little black on the wing-tips, and the tail is deeply forked. The feet are orangish-yellow. The call is a series of rapid notes "je-je-je-je", or a harsh "jeeer".

Distribution

Trudeau's tern is resident in the southern half of South America. It breeds in Uruguay, Brazil, Argentina and Chile and migrates in winter further north along the coast to Rio de Janeiro in the east and southern Peru in the west. It is a vagrant to the Falkland Islands and Paraguay, and the birds Audubon described from New Jersey were far outside the normal range.

References

{{Taxonbar, from=Q997524 Sterna Birds of Argentina Birds of Chile Birds of Uruguay Birds of the South Region Snowy-crowned tern Taxonomy articles created by Polbot Snowy-crowned tern