Sandwich tern

The Sandwich tern (Thalasseus sandvicensis)[2] is a tern in the family Laridae. It is very closely related to the lesser crested tern (T. bengalensis), Chinese crested tern (T. bernsteini), Cabot's tern (T. acuflavidus), and elegant tern (T. elegans) and has been known to interbreed with the lesser crested.

The Sandwich tern is a medium-large tern with grey upperparts, white underparts, a yellow-tipped black bill and a shaggy black crest which becomes less extensive in winter with a white crown. Young birds bear grey and brown scalloped plumage on their backs and wings. It is a vocal bird. It nests in a ground scrape and lays one to three eggs.

Like all Thalasseus terns, the Sandwich tern feeds by plunge diving for fish, usually in marine environments, and the offering of fish by the male to the female is part of the courtship display.

Sandwich tern
Thalasseus sandvicensis Rye Harbour 1
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Genus: Thalasseus
Species:
T. sandvicensis
Binomial name
Thalasseus sandvicensis
(Latham, 1787)
Synonyms

Sterna sandvicensis

Taxonomy

Sandwich Tern (Sterna sandvicensis) (6)
Sandwich tern in flight

The terns are small to medium-sized seabirds, gull-like in appearance, but usually with a more delicate, lighter build and shorter, weaker legs. They have long, pointed wings, which gives them a fast buoyant flight, and often a deeply forked tail. Most species are grey above and white below, and have a black cap which is reduced or flecked with white in the winter.[3]

The Sandwich tern was originally described by ornithologist John Latham in 1787 as Sterna sandvicensis, but was recently moved to its current genus Thalasseus (Boie, 1822) following mitochondrial DNA studies which confirmed that the three types of head pattern (white crown, black cap, and black cap with a white blaze on the forehead) found amongst the terns corresponded to distinct clades.[2] The current genus name is derived from Greek Thalassa, "sea", and sandvicensis, like the English name, refers to Sandwich, Kent, Latham's type locality. In birds, the specific name sandvicensis usually denotes that the species was first described from Hawaii, formerly known as the "Sandwich Islands", but the Sandwich tern does not occur there.[4]

This bird has no subspecies. A former subspecies are now treated as a separate species called Cabot's tern (T. acuflavidus), which breeds on the Atlantic coasts of North America, northern and eastern South America, and has wandered to Western Europe.

Description

Sterna sandvicensis MWNH 0433
Eggs, Collection Museum Wiesbaden

This is a medium-large tern, 37–43 cm (15–17 in) long with an 85–97 cm (33–38 in) wingspan, which is unlikely to be confused within most of its range, although the South American race could be confused with the elegant tern.

The Sandwich tern's thin sharp bill is black with a yellow tip, except in the yellow or orange billed South American race. Its short legs are black. Its upperwings are pale grey and its underparts white, and this tern looks very pale in flight, although the primary flight feathers darken during the summer.[5]

OneSandwichAmongLesserCrestedTerns
Sandwich tern (left) among lesser crested terns

The lesser crested tern and elegant tern differ in having all-orange bills; lesser crested also differs in having a grey rump and marginally stouter bill, and elegant in having a slightly longer, slenderer bill. Chinese crested tern is the most similar to Sandwich, but has a reversal of the bill colour, yellow with a black tip; it does not overlap in range with Sandwich tern so confusion is unlikely.

In winter, the adult Sandwich tern's forehead becomes white. Juvenile Sandwich terns have dark tips to their tails, and a scaly appearance on their back and wings, like juvenile roseate terns.[5]

The Sandwich tern is a vocal bird; its call is a characteristic loud grating kear-ik or kerr ink.[5]

Sandwich tern call

Behaviour

This species breeds in very dense colonies on coasts and islands, and exceptionally inland on suitable large freshwater lakes close to the coast. It nests in a ground scrape and lays one to three eggs. Unlike some of the smaller white terns, it is not very aggressive toward potential predators, relying on the sheer density of the nests—often only 20–30 cm (7.9–11.8 in) apart and nesting close to other more aggressive species such as Arctic terns and black-headed gulls to avoid predation.

Like all Thalasseus terns, the Sandwich tern feeds by plunge-diving for fish, almost invariably from the sea. It usually dives directly, and not from the "stepped-hover" favoured by Arctic terns. The offering of fish by the male to the female is part of the courtship display.

Status

The Sandwich tern has an extensive global range estimated at 100,000–1,000,000 km2 (39,000–386,000 sq mi). It has a population estimated at 460,000–500,000 individuals. Population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as least concern.[1]

The Sandwich tern is among the taxa to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.[6] Parties to the agreement are required to engage in a wide range of conservation actions which are describes in a detailed action plan. This plan should address key issues such as species and habitat conservation, management of human activities, research, education, and implementation.[7]

Sterna sandvicensis Brandseeschwalbe

T. sandvicensis approaching its waiting offspring with a fish

Sterna sandvicensis01

T. sandvicensis with common terns

Sandwich Tern from the Crossley ID Guide Britain and Ireland

ID composite

References

  1. ^ a b BirdLife International (2015). "Thalasseus sandvicensis". IUCN Red List of Threatened Species. IUCN. 2015: e.T22694591A85104473. Retrieved 28 May 2016.
  2. ^ a b Bridge, Eli S.; Jones, Andrew W.; Baker, Allan J. (2005). "A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution". Molecular Phylogenetics and Evolution. 35 (2): 459–469. doi:10.1016/j.ympev.2004.12.010. PMID 15804415.
  3. ^ Snow, David; Perrins, Christopher M., eds. (1998). The Birds of the Western Palearctic (BWP) concise edition (2 volumes). Oxford: Oxford University Press. p. 764. ISBN 0-19-854099-X.
  4. ^ Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 347, 383. ISBN 978-1-4081-2501-4.
  5. ^ a b c Hume, R. (2002). RSPB Birds of Britain and Europe. London: Dorling Kindersley. p. 186. ISBN 0-7513-1234-7.
  6. ^ "Annex 2: Waterbird species to which the Agreement applies". Agreement on the conservation of African-Eurasian migratory Waterbirds (AEWA). UNEP/ AEWA Secretariat. Retrieved 28 May 2016.
  7. ^ "Introduction". African-Eurasian Waterbird Agreement. UNEP/ AEWA Secretariat. Retrieved 28 May 2016.

Further reading

External links

Australian tern

The Australian tern or Australian gull-billed tern (Gelochelidon macrotarsa) is a tern in the family Laridae. The genus name is from Ancient Greek gelao, "to laugh", and khelidon, "swallow". It was previously considered conspecific with the gull-billed tern.

Cabot's tern

Cabot's tern (Thalasseus acuflavidus) is a tern in the family Laridae formerly considered as a subspecies of the Sandwich tern. It has since been shown to be more closely related to the elegant tern (Thalasseus elegans). The genus name is from Ancient Greek Thalasseus, "fisherman" from thalassa, "sea". The specific acuflavida is Latin from acus, "needle", and flavidus, "yellowish". The IOC recognizes the bird as distinct, but most other taxonomists, including both committees of the AOU, consider it conspecific with the Sandwich tern.The former species, T. s. eurygnatha (Saunders 1876), is sometimes treated as a separate species called the Cayenne tern (T. eurygnatha), which breeds on the Atlantic coast of South America from Argentina north to the Caribbean, intergrading with T. acuflavidus in the north of its range. The DNA analysis showed that Cayenne tern differed genetically from T. acuflavidus, but the difference was not sufficient to confirm it as a definite separate species.

Chinese crested tern

The Chinese crested tern (Thalasseus bernsteini) is a tern in the family Laridae, closely related to the Sandwich tern, T. sandvicensis, and the lesser crested tern, T. bengalensis. It is most similar to the former, differing only in the bill pattern, which is the reverse of the Sandwich tern's, being yellow with a black tip. From the lesser crested tern, which it overlaps in wintering distribution, it can be told by the white rump and paler grey mantle, as well as the black tip to the bill, which seen from up close also has a white point. The larger greater crested tern is also similar, differing in its stouter, all-yellow bill and darker grey mantle and rump, as well as in size.

It is a critically endangered species, previously thought extinct, with a mere four pairs rediscovered in 2000, nesting in a greater crested tern colony on an islet in the Matsu Islands (territory governed by Taiwan), just off the coast of Fujian Province, China, and wintering south to the Philippines. In the past, it had a wider distribution off the Chinese east coast north to Shandong Province. The decline is thought to be due to past hunting and egg collection for food. Past protection of this colony may be because of the islands' disputed status, administered by Taiwanese government (as part of Fujian Province of the ROC) but claimed by mainland China, the military sensitivity of the area restricting access. The islet has now been declared a wildlife sanctuary. It is possible that other small colonies may yet be found off the Chinese and Taiwanese coasts; migrant birds have been seen near the mouth of the Pachang River. The total population is speculated to be less than 50 birds.

In 2016, for the first time, Chinese crested terns were found breeding in South Korea. Setting up a new colony in such a faraway area would prove a boon for the species.The species is therefore the county bird of Lienchiang County (Matsu Islands).

Deveaux Bank, South Carolina

Deveaux Bank is a horseshoe-shaped sand spit island encompassing a 215-acre (87-hectare) bird sanctuary at the mouth of the North Edisto River in Charleston County, South Carolina. It is located on the Atlantic Coast between Edisto Island, South Carolina and Seabrook Island, South Carolina. Its average elevation is three feet. It has approximately 2.75 miles (4.43 kilometres) of sandy beaches on three sides (some of which are completely submerged at high tide) and a tidal lagoon on the side facing the mainland.

Elegant tern

The elegant tern (Thalasseus elegans) is a tern in the family Laridae. It breeds on the Pacific coasts of the southern United States and Mexico and winters south to Peru, Ecuador and Chile.

This species breeds in very dense colonies on coasts and islands, including Isla Rasa and Montague Island (Mexico), and exceptionally inland on suitable large freshwater lakes close to the coast. It nests in a ground scrape and lays one to two eggs. Unlike some of the smaller white terns, it is not very aggressive toward potential predators, relying on the sheer density of the nests (often only 20–30 cm apart) and nesting close to other more aggressive species such as Heermann's gulls to avoid predation.

The elegant tern feeds by plunge-diving for fish, almost invariably from the sea, like most Thalasseus 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 Pacific species has wandered to western Europe as a rare vagrant on a number of occasions, has nested in Spain and has interbred with the Sandwich tern in France; there is also one record from Cape Town, South Africa in January 2006, the first record for Africa. An Elegant Tern was recorded in the British Isles, in Pagham, West Sussex, in June 2017.

Farne Islands

The Farne Islands are a group of islands off the coast of Northumberland, England. There are between 15 and 20 islands depending on the state of the tide. They are scattered about 1 1⁄2 to 4 3⁄4 miles (2.4–7.6 km) from the mainland, divided into two groups, the Inner Group and the Outer Group. The main islands in the Inner Group are Inner Farne, Knoxes Reef and the East and West Wideopens (all joined together on very low tides) and (somewhat separated) the Megstone; the main islands in the Outer Group are Staple Island, the Brownsman, North and South Wamses, Big Harcar and the Longstone. The two groups are separated by Staple Sound. The highest point, on Inner Farne, is 62 feet (19 m) above mean sea level.

Gasparilla Island State Park

Gasparilla Island State Park is a Florida State Park located south of Boca Grande on Gasparilla Island off Charlotte Harbor and Pine Island Sound. Activities include swimming and fishing along with shelling, picnicking, and viewing the Historic Port Boca Grande Lighthouse. Visitors can also enjoy snorkeling, and nature study.

Among the wildlife of the park are West Indian manatee, gopher tortoise, bald eagle, osprey, least tern, royal tern, Sandwich tern, and black skimmer.

The park admission fee is $3.00 per vehicle or golf cart, $2.00 per pedestrian or bicycle, and a donation of $2.00 is requested for the lighthouse.

Amenities include four parking lots, two picnic areas with covered tables, beaches, and Historic Port Boca Grande Lighthouse on the southern end of the island. The Port Boca Grande Lighthouse contains a museum and gift shop, and is run by the Barrier Island Park Society, a nonprofit that supports the Gasparilla Island State Park. The park is open from 8:00 am till sundown year-round. The lighthouse is open from 10:00 am to 4:00 pm Monday–Saturday, and noon to 4:00 pm on Sundays; hours change off season; call for hours during the summer.

Gull-billed tern

The gull-billed tern (Gelochelidon nilotica), formerly Sterna nilotica, is a tern in the family Laridae. The genus name is from Ancient Greek gelao, "to laugh", and khelidon, "swallow". The specific niloticus is from Latin and means of the Nile. The Australian tern was previously considered a subspecies.

Lavells Lake

Lavells Lake is a local nature reserve in Woodley, Berkshire, England. The nature reserve is owned by Wokingham Borough Council and managed by the council in partnership with the Friends of Lavell's Lake. The nature reserve is within the Dinton Pastures Country Park.

Lesser crested tern

The lesser crested tern (Thalasseus bengalensis) is a tern in the family, Laridae.

Niayes

Niayes is a geographical area in northwestern Senegal which forms a coastal strip, with sand dunes adjoining the sea being backed by a string of fresh water lakes. The land is used for horticulture and the grazing of cattle, and provides suitable habitat for waterfowl and other birds. The Niayes Arrondissement is subdivided into four administrative regions.

The area is important both economically and for conservation, but is threatened by desertification.

Norderoog

Norderoog (Halligen Frisian: Noorderuug, Danish: Nørreog) is one of the ten German halligen islands of the North Frisian Islands in the Wadden Sea, which is part of the North Sea off the coast of Germany. A part of Hooge municipality, the island belongs to the Nordfriesland district.It is only temporarily inhabited by a bird warden from March to October. The refuge hut at the northeastern end is called Jens Wand Hütte, which is built on stilts to protect it from flooding. A former terp had been washed away. It has been the site of several ecological studies.

River Ythan

The Ythan is a river in the north-east of Scotland rising at Wells of Ythan near the village of Ythanwells and flowing south-eastwards through the towns of Fyvie, Methlick and Ellon before flowing into the North Sea near Newburgh, in Formartine.

The lower reach of the river is known as the Ythan Estuary, a Special Protection Area for conservation, particularly the breeding ground of three tern species (common tern, little tern and Sandwich tern) (Lumina, 2004).

The River Ythan has a length of 60 km and a catchment area of 680 km2. As figures of the discharge, 6 m3/s or 7,2 m3/s are given.

Roseate tern

The roseate tern (Sterna dougallii) is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and the specific dougallii refers to Scottish physician and collector Dr Peter McDougall (1777–1814). "Roseate" refers to the bird's pink breast in breeding plumage.

Rottumerplaat

Rottumerplaat (Dutch pronunciation: [ˌrɔtɵmərˈplaːt]) is one of the three islands that make up Rottum in the West Frisian Islands. The island is located in the North Sea off the Dutch coast. It is situated between the islands of Schiermonnikoog and Rottumeroog.

Access to the island is prohibited since Rottumerplaat is a resting and forage area for numerous bird species. Rijkswaterstaat, Staatsbosbeheer and the Ministry of Agriculture, Nature and Food Quality are responsible for the administration of the island. Twice a year marine debris is cleaned from the island.

Sediment deposition has caused the island to become significantly larger in recent years.

Rottumerplaat is the northernmost point of the Netherlands.

Thalasseus

Thalasseus, the crested terns, is a genus of seven species of terns in the Laridae family.

It has a worldwide distribution, and many of its species are abundant and well-known birds in their ranges. This genus had originally been created by Friedrich Boie in 1822, but had been abandoned until a 2005 study confirmed the need for a separate genus for the crested terns.These large terns breed in very dense colonies on coasts and islands, and exceptionally inland on suitable large freshwater lakes close to the coast. They nest in a ground scrape.

Thalasseus terns feed by plunge-diving for fish, almost invariably from the sea. They usually dive directly, and not from the "stepped-hover" favoured by, for example, the Arctic tern. The offering of fish by the male to the female is part of the courtship display.

These species have long thin sharp bills, usually a shade of yellow or orange except in the Sandwich tern and Cabot's tern where the bills are black with yellow tips in most subspecies. All species have a shaggy crest. In winter, the Thalasseus terns' foreheads become white.

Torryburn

Torryburn is a village and parish in Fife, Scotland, lying on the north shore of the Firth of Forth. It is one of a number of old port communities on this coast and at one point served as port for Dunfermline. It lies in the Bay of Torry in South Western Fife.

The civil parish has a population of 1,587 (in 2011).

Tupiniquins Ecological Station

Tupiniquins Ecological Station (Portuguese: Estação Ecológica dos Tupiniquins) is a coastal marine ecological station on the coast of São Paulo State, Brazil.

Tyuleniy Archipelago

The Tyuleniy Archipelago (Kazakh: Түлен аралдары Túlen araldary, Russian: Тюленьи острова) is an island group in the north-eastern Caspian Sea off the Mangyshlak Bay west of the Mangyshlak Peninsula and about 13 kilometres (8.1 miles) northwest of the Tupkaragan Peninsula, 27 kilometres (17 miles) north of Bautino. Perhaps the most substantial group of islands in the Caspian, they were first accurately mapped by Fedor Ivanovich Soimonov who led the 1719 Caspian Expedition, studying the Caspian Sea from 1719 to 1727.Administratively, the Tyuleniy Archipelago belongs to the Mangystau Region of Kazakhstan. It was named "Tyuleniy" —meaning "seal"— after the currently endangered Caspian seal.

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