96-421: The roseate tern ( Sterna dougallii ) is a species of 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. English naturalist George Montagu described the roseate tern in 1813. Genetically, it
192-514: A 67–76 cm (26–30 in) wingspan, which can be confused with the common tern , Arctic tern, and the larger, but similarly plumaged, Sandwich tern . The thin sharp bill is black, with a red base which develops through the breeding season, and is more extensive (to fully red) in the tropical and southern hemisphere subspecies. It is shorter-winged and has faster wing beats than common or Arctic tern. The upper wings are pale grey and its under parts white, and this tern looks very pale in flight, like
288-586: A bare tree branch. Depending on the species, one to three eggs make up the clutch . Most species feed on fish caught by diving from flight, but the marsh terns are insect-eaters, and some large terns will supplement their diet with small land vertebrates . Many terns are long-distance migrants , and the Arctic tern may see more daylight in a year than any other animal. Terns are normally monogamous , although trios or female-female pairings have been observed in at least three species. Most terns breed annually and at
384-535: A black cap to the head. The legs and bill are various combinations of red, orange, yellow, or black depending on species. The pale plumage is conspicuous from a distance at sea, and may attract other birds to a good feeding area for these fish-eating species. When seen against the sky, the white underparts also help to hide the hunting bird from its intended prey. The Inca tern has mainly dark plumage, and three species that mainly eat insects, black tern , white-winged tern , and black-bellied tern , have black underparts in
480-474: A black nape and crown (streaked white), and white cheeks. The grey mantle is 305 mm (12.0 in), and the scapulae are fringed brown, some tipped white. The upper wing is grey with a white leading edge, and the collar is completely white, as is the rump. The deeply forked tail is whitish, with grey outer webs. Arctic terns are long-lived birds, with many reaching fifteen to thirty years of age. They eat mainly fish and small marine invertebrates . The species
576-461: A competitor for nesting sites, the larger herring gull steals eggs and hatchlings. Camouflaged eggs help prevent this, as do isolated nesting sites. Scientists have experimented with bamboo canes erected around tern nests. Although they found fewer predation attempts in the caned areas than in the control areas, canes did not reduce the probability of predation success per attempt. While feeding, skuas , gulls, and other tern species will often harass
672-514: A decade, a pair fledged two chicks on the Skerries, off Anglesey after a RSPB project over previous years involving wardening, newly designed nest boxes being placed strategically around the islands along with lures playing roseate tern calls and hand-made decoys. In the UK the roseate tern has been designated for protection under the official government's national Biodiversity Action Plan . One of
768-478: A dozen Arctic terns breeding in the Netherlands shows average annual migrations of c. 48,700 km (30,300 mi). On their way south, these birds roughly followed the coastlines of Europe and Africa . Arctic terns usually migrate sufficiently far offshore that they are rarely seen from land outside the breeding season. The Arctic tern is a medium-sized bird around 33–36 cm (13–14 in) from
864-408: A fuller black cap than that species. As with other Sterna terns, roseate tern feeds by plunge-diving for fish , almost invariably from the sea; it is much more marine than allied terns, only rarely visiting freshwater lagoons on the coast to bathe and not fishing in fresh water. It usually dives directly, and not from the "stepped-hover" favoured by Arctic tern . The offering of fish by the male to
960-572: A measure of protection, but adults and eggs of some species are still used for food in the tropics. Terns range in size from the least tern , at 23 cm (9.1 in) in length and weighing 30–45 g (1.1–1.6 oz), to the Caspian tern at 48–56 cm (19–22 in), 500–700 g (18–25 oz). They are longer-billed, lighter-bodied, and more streamlined than gulls, and their long tails and long narrow wings give them an elegance in flight. Male and female plumages are identical, although
1056-497: A non-breeding plumage, which usually involves a white forehead and much-reduced black cap. Terns are long-lived birds and are relatively free from natural predators and parasites ; most species are declining in numbers due directly or indirectly to human activities, including habitat loss, pollution, disturbance, and predation by introduced mammals . The Chinese crested tern is critically endangered and three other species are classed as endangered . International agreements provide
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#17327829145201152-524: A return journey of more than 30,000 km (19,000 mi). A common tern that hatched in Sweden and was found dead five months later on Stewart Island , New Zealand , must have flown at least 25,000 km (16,000 mi). Actual flight distances are, of course, much greater than the shortest possible route. Arctic terns from Greenland were shown by radio geolocation to average 70,000 km (43,000 mi) on their annual migrations, while another from
1248-444: A scaly appearance. They have dark bands on the wings and short tails. In most species, the subsequent moult does not start until after migration, the plumage then becoming more like the adult, but with some retained juvenile feathers and a white forehead with only a partial dark cap. By the second summer, the appearance is very like the adult, and full mature plumage is usually attained by the third year. After breeding, terns moult into
1344-402: A small Sandwich tern, although the outermost primary flight feathers darken during the summer. The adults have very long, flexible tail streamers and orange-red legs. In summer, the underparts of adults take on the pinkish tinge which gives this bird its name. In winter, the forehead becomes white and the bill black. Juvenile roseate terns have a scaly appearance like juvenile Sandwich Terns, but
1440-452: A sooty. Although several other species are known to live in captivity for up to 20 years, their greatest recorded ages are underestimates because the birds can outlive their rings . Interbreeding between tern species is rare, and involves closely related species when it occurs. Hybrids recorded include common tern with roseate, Sandwich with lesser-crested, and black with white-winged. Most terns hunt fish by diving, often hovering first, and
1536-467: A straight route as was previously assumed. The birds follow a somewhat convoluted course in order to take advantage of prevailing winds. The average Arctic tern lives about 30 years and will, based on the above research, travel some 2.4 million km (1.5 million mi) during its lifetime, the equivalent of a roundtrip from Earth to the Moon more than three times. A 2013 tracking study of half
1632-480: A whiter forecrown. The species has a variety of calls ; the two most common being the alarm call , made when possible predators (such as humans or other mammals ) enter the colonies, and the advertising call . While the Arctic tern is similar to the common and roseate terns , its colouring, profile, and call are slightly different. Compared to the common tern, it has a longer tail and mono-coloured bill, while
1728-426: A winter plumage, typically showing a white forehead. Heavily worn or aberrant plumages such as melanism and albinism are much rarer in terns than in gulls. Terns have a wide repertoire of vocalisations. For example, the common tern has a distinctive alarm , kee-yah , also used as a warning to intruders, and a shorter kyar , given as an individual takes flight in response to a more serious threat; this quietens
1824-504: Is abundant, with an estimated two million individuals. While the trend in the number of individuals in the species as a whole is not known, exploitation in the past has reduced this bird's numbers in the southern reaches of its ranges. The genus name Sterna is derived from Old English "stearn", "tern". The specific paradisaea is from Late Latin paradisus , "paradise". The Scots names pictarnie , tarrock and their many variants are also believed to be onomatopoeic , derived from
1920-496: Is also a factor. The Peruvian tern was initially damaged by the collapse of anchoveta stocks in 1972, but breeding colonies have subsequently been lost due to building, disturbance and pollution in their coastal wetlands. The Australasian fairy tern is described as " vulnerable ". Disturbance by humans, dogs and vehicles, predation by introduced species and inappropriate water level management in South Australia are
2016-562: Is available it will eat small crabs, fish, crayfish , grasshoppers and other large insects, lizards and amphibians . Warm-blooded prey includes mice and the eggs and chicks of other beach-breeding birds; least terns, little terns and members of its own species may be victims. The greater crested tern will also occasionally catch unusual vertebrate species such as agamid lizards and green sea turtle hatchlings, and follows trawlers for discards. The eyes of terns cannot accommodate under water, so they rely on accurate sighting from
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#17327829145202112-569: Is declining due to egg collection, human disturbance and the loss of coastal wetlands in China. Three other species are categorised as " endangered ", with declining populations of less than 10,000 birds. The South Asian black-bellied tern is threatened by habitat loss, egg collecting for food, pollution and predation. In New Zealand, the black-fronted tern is facing a rapid fall in numbers due to predation by introduced mammals and Australian magpies . Disturbance by cattle and sheep and by human activities
2208-481: Is dependent on sea-ice cover, but unlike breeding species, it is able to move to a different area if necessary, and can be used as a control to investigate the effect of climate change on breeding species. The Arctic tern has appeared on the postage stamps of several countries and dependent territories. The territories include Åland , Alderney , and Faroe Islands . Countries include Canada, Finland , Iceland , and Cuba . The Arctic tern featured prominently in
2304-523: Is most closely related to the white-fronted tern ( S. striata ), with their common ancestor a sister lineage to the black-naped tern ( S. sumatrana ). This species has a number of geographical subspecies, differing mainly in bill colour and minor plumage details. S. d. dougallii breeds on the Atlantic coasts of Europe and North America, and winters south to the Caribbean and west Africa. Both
2400-471: Is significantly affected by this hunting, with adult survival 10% lower than would otherwise be expected. In the West Indies, the eggs of roseate and sooty terns are believed to be aphrodisiacs , and are disproportionately targeted by egg collectors. Tern skins and feathers have long been used for making items of clothing such as capes and hats, and this became a large-scale activity in the second half of
2496-419: Is similar, although there is a greater emphasis on protection. Arctic tern Sterna portlandica Sterna pikei The Arctic tern ( Sterna paradisaea ) is a tern in the family Laridae . This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe (as far south as Brittany ), Asia, and North America (as far south as Massachusetts ). The species
2592-537: Is strongly migratory , seeing two summers each year as it migrates along a convoluted route from its northern breeding grounds to the Antarctic coast for the southern summer and back again about six months later. Recent studies have shown average annual round-trip lengths of about 70,900 km (44,100 mi) for birds nesting in Iceland and Greenland and about 48,700 km (30,300 mi) for birds nesting in
2688-561: Is sufficiently stable. A few species nest in small or dispersed groups, but most breed in colonies of up to a few hundred pairs, often alongside other seabirds such as gulls or skimmers. Large tern species tend to form larger colonies, which in the case of the sooty tern can contain up to two million pairs. Large species nest very close together and sit tightly, making it difficult for aerial predators to land among them. Smaller species are less closely packed and mob intruders. Peruvian and Damara terns have small dispersed colonies and rely on
2784-594: Is uncertain whether they are sighting the phytoplankton on which the fish feed, or other feeding birds. The red colouring reduces ultraviolet sensitivity, which in any case is an adaptation more suited to terrestrial feeders like the gulls, and this protects the eye from UV damage. The inaccessibility of many tern colonies gave them a measure of protection from mammalian predators, especially on islands, but introduced species brought by humans can seriously affect breeding birds. These can be predators such as foxes , raccoons , cats and rats , or animals that destroy
2880-414: Is unique in that it lays its single egg on a bare tree branch. Tropical species usually lay just one egg, but two or three is typical in cooler regions if there is an adequate food supply. The time taken to complete the clutch varies, but for temperate species incubation takes 21–28 days. The eggs of most gulls and terns are brown with dark splotches, so they are difficult for predators to spot on
2976-436: Is usually a depression in the ground, which may or may not be lined with bits of grass or similar materials. The eggs are mottled and camouflaged. Both sexes share incubation duties. The young hatch after 22–27 days and fledge after 21–24 days. If the parents are disturbed and flush from the nest frequently the incubation period could be extended to as long as 34 days. When hatched, the chicks are downy . Being precocial ,
Roseate tern - Misplaced Pages Continue
3072-548: The Chlidonias species are the marsh terns, and all other species comprise the sea terns. Terns have a worldwide distribution, breeding on all continents including Antarctica. The northernmost and southernmost breeders are the Arctic tern and Antarctic tern respectively. Many terns breeding in temperate zones are long-distance migrants , and the Arctic tern sees more annual daylight than any other animal as it migrates from its northern breeding grounds to Antarctic waters,
3168-1079: The Farne Islands in Northumberland tagged 'G82' covered a staggering 96,000 km in just 10 months from the end of one breeding season to the start of the next, travelling not just the length of the Atlantic Ocean and the width of the Indian Ocean, but also half way across the South Pacific to the boundary between the Ross and Amundsen Seas before returning back west. Most terns breed on open sandy or rocky areas on coasts and islands. The yellow-billed , large-billed , and black-fronted terns breed only on rivers, and common, least and little terns also sometimes use inland locations. The marsh terns , Trudeau's tern and some Forster's terns nest in inland marshes. The black noddy and
3264-589: The Farne Islands , Northumberland , UK, in the northern summer of 1982 that reached Melbourne , Australia in October, just three months after fledging – a journey of more than 22,000 km (14,000 mi). Another example is that of a chick ringed in Labrador , Canada , on 23 July 1928. It was found in South Africa four months later. A 2010 study using tracking devices attached to the birds showed that
3360-611: The H5N3 variant being found in an outbreak involving South African birds. Several species of terns have been implicated as carriers of West Nile virus . Terns and their eggs have long been eaten by humans and island colonies were raided by sailors on long voyages since the eggs or large chicks were an easily obtained source of protein . Eggs are still illegally harvested in southern Europe, and adults of wintering birds are taken as food in West Africa and South America. The roseate tern
3456-406: The Netherlands . These are by far the longest migrations known in the animal kingdom. The Arctic tern nests once every one to three years (depending on its mating cycle). Arctic terns are medium-sized birds. They have a length of 28–39 cm (11–15 in) and a wingspan of 65–75 cm (26–30 in). They are mainly grey and white plumaged, with a red/orange beak and feet, white forehead,
3552-489: The black-naped tern ( S. sumatrana ), lesser crested tern ( Thalasseus bengalensis ), greater crested tern ( T. bergii ), fairy tern ( Sternula nereis ), bridled tern ( Onychoprion anaethetus ) and silver gull ( Chroicocephalus novaehollandiae ). It nests in a ground scrape, often in a hollow or under dense vegetation, and lays one or two (rarely three) eggs. It is less defensive of its nest and young than other white terns, often relying on Arctic and common terns in
3648-503: The common tern . It lays from one to three eggs per clutch, most often two. It is one of the most aggressive terns, fiercely defensive of its nest and young. It will attack humans and large predators, usually striking the top or back of the head. Although it is too small to cause serious injury to an animal of a human's size, it is still capable of drawing blood, and is capable of repelling many raptorial birds, polar bears and smaller mammalian predators such as foxes and cats. The nest
3744-453: The crustacean Reighardia sternae , and tapeworms such as Ligula intestinalis and members of the genera Diphyllobothrium and Schistocephalus . Terns are normally free of blood parasites, unlike gulls that often carry Haemoproteus species. An exception is the brown noddy, which sometimes harbours protozoa of that genus. In 1961 the common tern was the first wild bird species identified as being infected with avian influenza,
3840-440: The cryptic plumage of the eggs and young for protection. The male selects a territory , which he defends against conspecifics , and re-establishes a pair bond with his mate or attracts a new female if necessary. Courtship involves ritualised flight and ground displays, and the male often presents a fish to his partner. Most species have little or no nest, laying the eggs onto bare ground, but Trudeau's tern, Forster's tern and
3936-420: The cytochrome b gene sequence found a close relationship between terns and a group of waders in the suborder Thinocori . These results are in disagreement with other molecular and morphological studies, and have been interpreted as showing either a large degree of molecular convergent evolution between the terns and these waders, or the retention of an ancient genotype . Research in 2007 had suggested that
Roseate tern - Misplaced Pages Continue
4032-533: The skimmers ( Rynchops ). They are slender, lightly built birds with long, forked tails, narrow wings, long bills, and relatively short legs. Most species are pale grey above and white below with a contrasting black cap to the head, but the marsh terns , the black-bellied tern , the Inca tern , and some noddies have dark body plumage for at least part of the year. The sexes are identical in appearance, but young birds are readily distinguishable from adults. Terns have
4128-461: The spotted redshank , quite distinct from other terns. In the late 19th century, these birds were hunted for their plumes which were used to decorate hats. More recently, their numbers have decreased in some regions due to increased competition and predation by large gulls , whose numbers have increased in recent times. This species, as of 2019, is one of the UK's rarest breeding seabird. The largest European colony, accounting for more than 75% of
4224-503: The white tern nest above ground level on cliffs or in trees. Migratory terns move to the coast after breeding, and most species winter near land, although some marine species, like the Aleutian tern , may wander far from land. The sooty tern is entirely oceanic when not breeding, and healthy young birds are not seen on land for up to five years after fledging until they return to breed. They lack waterproof plumage, so they cannot rest on
4320-617: The 1980s, organochlorides caused severe declines in the Great Lakes area of the US. Because of their sensitivity to pollutants, terns are sometimes used as indicators of contamination levels. Habitat enhancements used to increase the breeding success of terns include floating nest platforms for black, common and Caspian terns, and artificial islands created for a number of different species. More specialised interventions include providing nest boxes for roseate terns, which normally nest in
4416-622: The Arctic tern varies depending on location and time, but is usually carnivorous . In most cases, it eats small fish or marine crustaceans . Fish species comprise the most important part of the diet, and account for more of the biomass consumed than any other food. Prey species are immature (1–2-year-old) shoaling species such as herring , cod , sandlances , and capelin . Among the marine crustaceans eaten are amphipods , crabs and krill . Sometimes, these birds also eat molluscs , marine worms, or berries , and on their northern breeding grounds, insects . Arctic terns sometimes dip down to
4512-462: The Arctic, and gull-billed terns in little tern colonies. Adults may be robbed of their catch by avian kleptoparasites such as frigatebirds , skuas, other terns or large gulls. External parasites include chewing lice of the genus Saemundssonia , feather lice and fleas such as Ceratophyllus borealis . Lice are often host specific, and the closely related common and Arctic terns carry quite different species. Internal parasites include
4608-878: The Cayenne tern, in the Caribbean . Terns are protected by international legislation such as the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) and the US-Canada Migratory Bird Treaty Act of 1918 . Parties to the AWEA agreement are required to engage in a wide range of conservation strategies described in a detailed action plan. The plan is intended to address key issues such as species and habitat conservation , management of human activities, research, education, and implementation. The North American legislation
4704-460: The Conservation of African-Eurasian Migratory Waterbirds applies. The population in New England was reduced in the late nineteenth-century because of hunting for the millinery trade. Exploitation continues in western Greenland , where the population of the species has been reduced greatly since 1950. In Iceland, the Arctic tern has been regionally uplisted to Vulnerable as of 2018, due to
4800-463: The English words from Scandinavian equivalents such as Danish and Norwegian terne or Swedish tärna , and ultimately from Old Norse þerna . Linnaeus adopted "stearn" or "sterna" (which the naturalist William Turner had used in 1544 as a Latinisation of an English word, presumably "stern", for the black tern) or a North Germanic equivalent for his genus name Sterna . The cladogram shows
4896-471: The European and North American populations have been in long-term decline, though active conservation measures have reversed the decline in the last few years at some colonies, most notably at Rockabill Island off the coast of Dublin, Ireland, which now holds most of the European population (about 1200 pairs). The tropical forms S. d. korustes and S. d. bangsi are resident breeders from east Africa across
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#17327829145204992-523: The European population, is in Ireland, at Rockabill Island , County Dublin . In 2013, 1213 pairs nested at Rockabill. The colony at Lady's Island Lake , County Wexford , is also of crucial importance, with 155 pairs nesting there in 2013. With their favouring partly hidden nest sites, the provision of nestboxes has proven a dramatic conservation success, with the birds taking to them very readily. This results in greatly increased breeding productivity with
5088-580: The Inca, Damara, and river terns , are expected to decline in the future due to habitat loss and disturbance. Some tern subspecies are endangered, including the California least tern and the Easter Island race of the grey noddy. Most tern species are declining in numbers due to the loss or disturbance of breeding habitat, pollution and increased predation. Gull populations have increased over
5184-470: The Indian Ocean to Japan . They have more red on the bill. The long-billed and short-winged S. d. gracilis breeds in Australia and New Caledonia . The north-western Indian Ocean holds populations of S. d. arideensis . Some authors suggest that only three subspecies arideensis , gracilis and nominate dougallii should be retained. This is a small-medium tern, 33–36 cm (13–14 in) long with
5280-505: The above examples are not unusual for the species. In fact, the study showed that previous research had seriously underestimated the annual distances travelled by the Arctic tern. Eleven birds that bred in Greenland or Iceland covered 70,900 km (44,100 mi) on average in a year, with a maximum of 81,600 km (50,700 mi). The difference from previous estimates is due to the birds taking meandering courses rather than following
5376-461: The air before they plunge-dive. Like other seabirds that feed at the surface or dive for food, terns have red oil droplets in the cones of their retinas ; birds that have to look through an air/water interface have more deeply coloured carotenoid pigments in the oil drops than other species. The pigment also improves visual contrast and sharpens distance vision, especially in hazy conditions, and helps terns to locate shoals of fish, although it
5472-430: The area near the wingtip being translucent. The tail is white, and the underparts pale grey. Both sexes are similar in appearance. The winter plumage is similar, but the crown is whiter and the bills are darker. Juveniles differ from adults in their black bill and legs, "scaly" appearing wings, and mantle with dark feather tips, dark carpal wing bar, and short tail streamers. During their first summer, juveniles also have
5568-472: The beach. The precocial chicks fledge in about four weeks after hatching. Tropical species take longer because of the poorer food supply. Both parents incubate the eggs and feed the chicks, although the female does more incubating and less fishing than her partner. Young birds migrate with the adults. Terns are generally long-lived birds, with individuals typically returning for 7–10 breeding seasons. Maximum known ages include 34 for an Arctic tern and 32 for
5664-513: The birds and steal their food. The total population for the arctic tern is estimated at more than two million individuals, with more than half of the population in Europe. The breeding range is very large, and although the population is considered to be decreasing, this species is evaluated as a species of least concern by the IUCN . Arctic terns are among the species to which the Agreement on
5760-410: The birds could lead them to fish shoals. Overfishing of small fish such as sand eels can lead to steep declines in the colonies relying on these prey items. More generally, the loss or disruption to tern colonies caused by human activities has caused declines in many species. Pollution has been a problem in some areas, and in the 1960s and 1970s DDT caused egg loss through thinning of the shells. In
5856-462: The breeding season. Three of the Anous noddies have dark plumage with a pale head cap, the other two (formerly separated in the genus Procelsterna paler grey. The reason for their dark plumage is unknown, but it has been suggested that in tropical areas, where food resources are scarce, the less conspicuous colouration makes it harder for other noddies to detect a feeding bird. Plumage type, especially
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#17327829145205952-422: The chicks begin to move around and explore their surroundings within one to three days after hatching. Usually they do not stray far from the nest. Chicks are brooded by the adults for the first ten days after hatching. Both parents care for hatchlings. Chick diets always include fish, and parents selectively bring larger prey items to chicks than they eat themselves. Males bring more food than females. Feeding by
6048-418: The crash of sandeel ( Ammodytes spp.) stocks. At the southern part of their range, the Arctic tern has been reducing in numbers. Much of this is due to a lack of food. However, most of these birds' range is extremely remote, with no apparent trend in the species as a whole. The Arctic terns' dispersal pattern is affected by changing climatic conditions, and its ability to feed in its Antarctic wintering
6144-459: The distinction in his 1758 Systema Naturae , placing the gulls in the genus Larus and the terns in Sterna . He gave Sterna the description rostrum subulatum , " awl-shaped bill", referring to the long, pointed bills typical of this group of birds, a feature that distinguishes them from the thicker-billed gulls. Behaviour and morphology suggest that the terns are more closely related to
6240-450: The distinctive call. Due to the difficulty in distinguishing the two species, all the informal common names are shared with the common tern . The Arctic tern has a continuous worldwide circumpolar breeding distribution; there are no recognized subspecies . It can be found in coastal regions in cooler temperate parts of North America and Eurasia during the northern summer. During the southern summer, it can be found at sea, reaching
6336-447: The early twenty-first century, the terns were historically treated as a separate family, Sternidae. Most terns were formerly treated as belonging to one large genus, Sterna , with just a few dark species placed in other genera; in one 1959 paper, only the noddies and the Inca tern were excluded from Sterna . A recent analysis of DNA sequences supported the splitting of Sterna into several smaller genera. One study of part of
6432-484: The eighth century, and appears in the poem The Seafarer , written in the ninth century or earlier. Variants such as "tearn" occurred by the eleventh century, although the older form lingered on in Norfolk dialect for several centuries. As now, the term was used for the inland black tern as well as the marine species. Some authorities consider "tearn" and similar forms to be variants of "stearn", while others derive
6528-546: The female is part of the courtship display. Unusual for a tern, the roseate tern shows some kleptoparasitic behaviour, stealing fish from other seabirds, at British colonies most often from puffins . This habit greatly increases their food-collecting ability during bad weather when fish swim deeper, out of reach of plunge-diving terns, but still within reach of the deeper-diving Puffins. This species breeds in colonies on coasts and islands, at times with other seabirds. In Australian colonies, it has been recorded nesting alongside
6624-430: The ground involves strutting with a raised tail and lowered wings. After this, both birds will usually fly and circle each other. Both sexes agree on a site for a nest, and both will defend the site. During this time, the male continues to feed the female. Mating occurs shortly after this. Breeding takes place in colonies on coasts, islands and occasionally inland on tundra near water. It often forms mixed flocks with
6720-470: The gulls than to the skimmers or skuas, and although Charles Lucien Bonaparte created the family Sternidae for the terns in 1838, for many years they were considered to be a subfamily, Sterninae, of the gull family, Laridae. Relationships between various tern species, and between the terns and the other Charadriiformes, were formerly difficult to resolve because of a poor fossil record and the misidentification of some finds. Following genetic research in
6816-595: The habitat, including rabbits , goats and pigs . Problems arise not only on formerly mammal-free islands, as in New Zealand, but also where an alien carnivore , such as the American mink in Scotland , presents an unfamiliar threat. Adult terns may be hunted by owls and raptors , and their chicks and eggs may be taken by herons , crows or gulls. Less obvious nest predators include ruddy turnstones in
6912-406: The head pattern, is linked to the phylogeny of the terns, and the pale-capped, dark-bodied noddies are believed to have diverged earlier than the other genera from an ancestral white-headed gull, followed by the partially black-headed Onychoprion and Sternula groupings. Juvenile terns typically have brown- or yellow-tinged upperparts, and the feathers have dark edges that give the plumage
7008-586: The last century because of reduced persecution and the availability of food from human activities, and terns have been forced out of many traditional nesting areas by the larger birds. A few species are defying the trend and showing local increases, including the Arctic tern in Scandinavia , Forster's tern around the Great Lakes, the Sandwich tern in eastern North America and its yellow-billed subspecies,
7104-530: The least and little terns , and can help humans distinguish similar species, such as common and arctic terns , since flight calls are unique to each species. The bird order Charadriiformes contains 18 coastal seabird and wader families . Within the order, the terns form a lineage with the gulls , and, less closely, with the skimmers , skuas , and auks . Early authors such as Conrad Gessner , Francis Willughby , and William Turner did not clearly separate terns from gulls, but Linnaeus recognised
7200-614: The main differences from the roseate are its slightly darker colour and longer wings. The Arctic tern's call is more nasal and rasping than that of the common, and is easily distinguishable from that of the roseate. This bird's closest relatives are a group of South Polar species, the South American ( Sterna hirundinacea ), Kerguelen ( S. virgata ), and Antarctic ( S. vittata ) terns. The immature plumages of Arctic tern were originally described as separate species, Sterna portlandica and Sterna pikei . Breeding begins around
7296-533: The main reasons for its decline. Five species are " near threatened ", indicating less severe concerns or only potential vulnerability. The elegant tern is so categorised because 95% of the population breeds on one island, Isla Rasa in the Gulf of California , and the Kerguelen tern has a population of less than 5,000 adults breeding on small and often stormy islands in the southern Indian Ocean . Three species,
7392-420: The main reasons given in the UK plan for threat to the species is global warming , creating an alteration of vertical profile distribution for its food source fishes. The roseate tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds ( AEWA ) applies. The Canadian Wildlife Service lists the roseate tern as Threatened. The U.S. Department of Interior lists
7488-588: The male can be 2–5% larger than the female and often has a relatively larger bill. Sea terns have deeply forked tails, and at least a shallow "V" is shown by all other species. The noddies (genera Anous , Procelsterna and Gygis ) have unusual notched-wedge shaped tails, the longest tail feathers being the middle-outer, rather than the central or outermost. Although their legs are short, terns can run well. They rarely swim, despite having webbed feet, usually landing on water only to bathe. The majority of sea terns have light grey or white body plumage as adults, with
7584-430: The marsh terns construct floating nests from the vegetation in their wetland habitats. Black and lesser noddies build nests of twigs, feathers and excreta on tree branches, and brown , blue , and grey noddies make rough platforms of grass and seaweed on cliff ledges, in cavities or on other rocky surfaces. The Inca tern nests in crevices, caves and disused burrows, such as that of a Humboldt penguin . The white tern
7680-520: The nineteenth century when it became fashionable to use feathers in hatmaking . This trend started in Europe but soon spread to the Americas and Australia. White was the preferred colour, and sometimes wings or entire birds were used. Terns have sometimes benefited from human activities, following the plough or fishing boats for easy food supplies, although some birds get trapped in nets or swallow plastic. Fishermen looked for feeding tern flocks, since
7776-628: The noddies were not terns at all, but were basal to all the other genera in Laridae, a taxonomy that was followed by the IOC World Bird List for several years up to 2023, but more comprehensive analysis has now shown that the noddies are basal to only the other terns, not the whole family; this has now been followed by the IOC World Bird List version 14.1 in 2024. The word "stearn" was used for these birds in Old English as early as
7872-457: The northeastern population as Endangered and the Caribbean population as Threatened. Tern Terns are seabirds in the family Laridae , subfamily Sterninae , that have a worldwide distribution and are normally found near the sea , rivers , or wetlands . Terns are treated in eleven genera in a subgroup of the family Laridae, which also includes several genera of gulls and
7968-558: The northern edge of the Antarctic ice. The Arctic tern is famous for its migration; it flies from its Arctic breeding grounds to the Antarctic and back again each year. The shortest distance between these areas is 19,000 km (12,000 mi). The long journey ensures that this bird sees two summers per year and more daylight than any other creature on the planet. One example of this bird's remarkable long-distance flying abilities involves an Arctic tern ringed as an unfledged chick on
8064-463: The parents lasts for roughly a month before being weaned off slowly. After fledging, the juveniles learn to feed themselves, including the difficult method of plunge-diving. They will fly south to winter with the help of their parents. Arctic terns are long-lived birds that spend considerable time raising only a few young, and are thus said to be K-selected . A 1957 study in the Farne Islands estimated an annual survival rate of 82%. The diet of
8160-471: The particular approach technique used can help to distinguish similar species at a distance. Sea terns often hunt in association with porpoises or predatory fish, such as bluefish , tuna or bonitos , since these large marine animals drive the prey to the surface. Sooty terns feed at night as the fish rise to the surface, and are believed to sleep on the wing since they become waterlogged easily. Terns of several species will feed on invertebrates , following
8256-435: The plough or hunting on foot on mudflats . The marsh terns normally catch insects in the air or pick them off the surface of fresh water. Other species will sometimes use these techniques if the opportunity arises. An individual tern's foraging efficiency increases with its age. The gull-billed tern is an opportunist predator, taking a wide variety of prey from marine, freshwater and terrestrial habitats. Depending on what
8352-472: The protection given to the young from predatory birds like herring gulls . At the UK's most important colony, on Coquet Island , Northumberland , the population rose from 25 pairs 1997 to 154 pairs in 2022 after nestboxes were provided. Similar measures have been undertaken at the Anglesey tern colonies along with clearance of vegetation, in particular Tree Mallow . In 2018, for the first time in more than
8448-512: The relationships between the tern genera, and the currently recognised species, based on mitochondrial DNA studies, are listed below: Anous Gygis Onychoprion Sternula Phaetusa Gelochelidon Hydroprogne Larosterna Chlidonias Thalasseus Sterna In addition to extant species, the fossil record includes a Miocene palaeospecies , Sterna milne-edwardsii . The genera Anous , Procelsterna and Gygis are collectively known as noddies,
8544-406: The same time of year, but some tropical species may nest at intervals shorter than 12 months or asynchronously . Most terns become sexually mature when aged three, although some small species may breed in their second year. Some large sea terns, including the sooty and bridled terns , are four or older when they first breed. Terns normally breed in colonies , and are site-faithful if their habitat
8640-421: The sea. Where they spend the years prior to breeding is unknown. The terns are birds of open habitats that typically breed in noisy colonies and lay their eggs on bare ground with little or no nest material. Marsh terns construct floating nests from the vegetation in their wetland habitats, and a few species build simple nests in trees, on cliffs or in crevices. The white tern , uniquely, lays its single egg on
8736-454: The shelter of tallish vegetation, and using artificial eelgrass mats to encourage common terns to nest in areas not vulnerable to flooding. A number of terns face serious threats, and the Chinese crested tern is classed as " critically endangered " by BirdLife International . It has a population of fewer than 50 birds and a breeding range of just 9 km (3.5 sq mi). It
8832-519: The surface of the water to catch prey close to the surface. They may also chase insects in the air when breeding. It is also thought that Arctic terns may, in spite of their small size, occasionally engage in kleptoparasitism by swooping at birds so as to startle them into releasing their catches. Several species are targeted—conspecifics, other terns (like the common tern), and some auk and grebe species. While nesting, Arctic terns are vulnerable to predation by cats and other animals. Besides being
8928-448: The surrounding colony to defend them. In smaller colonies, they may rarely mate with these other tern species. The white-bellied sea-eagle ( Haliaeetus leucogaster ) and silver gull are known to prey on eggs and chicks, while the turnstone ( Arenaria interpres ), black rat ( Rattus rattus ) and King's skink ( Egernia kingii ) are suspected predators. The call of the roseate tern is a very characteristic chuwit , similar to that of
9024-417: The third or fourth year. Arctic terns mate for life and, in most cases, return to the same colony each year. Courtship is elaborate, especially in birds nesting for the first time. Courtship begins with a so-called "high flight", where a female will chase the male to a high altitude and then slowly descend. This display is followed by "fish flights", where the male will offer fish to the female. Courtship on
9120-412: The tip of its beak to the tip of its tail. The wingspan is 76–85 cm (30–33 in). The weight is 86–127 g (3.0–4.5 oz). The beak is dark red, as are the short legs and webbed feet. Like most terns, the Arctic tern has high aspect ratio wings and a tail with a deep fork. The adult plumage is grey above, with a black nape and crown and white cheeks. The upperwings are pale grey, with
9216-488: The usually noisy colony while its residents assess the danger. Other calls include a down-slurred keeur given when an adult is approaching the nest with a fish, and a kip uttered during social contact. Parents and chicks can locate one another by call, and siblings also recognise each other's vocalisations from about the twelfth day after hatching, which helps to keep the brood together. Vocal differences reinforce species separation between closely related birds such as
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