Forster's Tern
Encyclopedia
The Forster's Tern, Sterna forsteri, is a member of the tern
family Sternidae. It breeds inland in North America
and winters
south to the Caribbean
and northern South America
.
This species is rare but annual in western Europe
, and has wintered in Ireland
and Great Britain
on a number of occasions. No European tern winters so far north.
This species breeds in colonies in marshes. It nests in a ground scrape and lays three or more eggs. Like all white terns, it is fiercely defensive of its nest and young.
The Forster's Tern feeds by plunge-diving for fish, but will also hawk for insects in its breeding marshes. It usually feeds from saline environments in winter, like most Sterna terns. It usually dives directly, and not from the "stepped-hover" favoured by the Arctic Tern
. The offering of fish by the male to the female is part of the courtship display.
This is a small tern, 33–36 cm long with a 64–70 cm wingspan. It is most similar to the Common Tern
. It has pale grey upperparts and white underparts. Its legs are red and its bill is red, tipped with black. In winter, the forehead becomes white and a characteristic black eyemask remains. Juvenile Forster's Terns are similar to the winter adult. The call is a harsh noise like a Black-headed Gull
.
This species is unlikely to be confused with the Common Tern in winter because of the black eyemask, but is much more similar in breeding plumage. Forster's has a grey centre to its white tail, and the upperwings are pure white, without the darker primary wedge of Common.
This bird is named after the naturalist Johann Reinhold Forster
.
Tern
Terns are seabirds in the family Sternidae, previously considered a subfamily of the gull family Laridae . They form a lineage with the gulls and skimmers which in turn is related to skuas and auks...
family Sternidae. It breeds inland in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and winters
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
south to the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and northern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
This species is rare but annual in western Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, and has wintered in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
and Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
on a number of occasions. No European tern winters so far north.
This species breeds in colonies in marshes. It nests in a ground scrape and lays three or more eggs. Like all white terns, it is fiercely defensive of its nest and young.
The Forster's Tern feeds by plunge-diving for fish, but will also hawk for insects in its breeding marshes. It usually feeds from saline environments in winter, like most Sterna terns. It usually dives directly, and not from the "stepped-hover" favoured by the Arctic Tern
Arctic Tern
The Arctic Tern is a seabird of the tern family Sternidae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe, Asia, and North America...
. The offering of fish by the male to the female is part of the courtship display.
This is a small tern, 33–36 cm long with a 64–70 cm wingspan. It is most similar to the Common Tern
Common Tern
The Common Tern is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding in temperate and sub-Arctic regions of Europe, Asia and east and central North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. It is sometimes...
. It has pale grey upperparts and white underparts. Its legs are red and its bill is red, tipped with black. In winter, the forehead becomes white and a characteristic black eyemask remains. Juvenile Forster's Terns are similar to the winter adult. The call is a harsh noise like a Black-headed Gull
Black-headed Gull
The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...
.
This species is unlikely to be confused with the Common Tern in winter because of the black eyemask, but is much more similar in breeding plumage. Forster's has a grey centre to its white tail, and the upperwings are pure white, without the darker primary wedge of Common.
This bird is named after the naturalist Johann Reinhold Forster
Johann Reinhold Forster
Johann Reinhold Forster was a German Lutheran pastor and naturalist of partial Scottish descent who made contributions to the early ornithology of Europe and North America...
.
External links
- Forster's Tern Species Account - Cornell Lab of Ornithology
- Forster's Tern - Sterna forsteri - USGS Patuxent Bird Identification InfoCenter
- Forster's Tern Information and Photos - South Dakota Birds and Birding
- Field Guide Page on Flickr