Tern
Terns Temporal range: Early Miocene to present
| |
---|---|
Greater crested tern in first-year plumage | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Laridae |
Subfamily: | Sterninae Bonaparte, 1838 |
Genera | |
Terns are
Terns are long-lived birds and are relatively free from natural predators and
Description
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),[1][2] to the Caspian tern at 48–56 cm (19–22 in), 500–700 g (18–25 oz).[3][4] 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 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.[5] 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.[6][7] Although their legs are short, terns can run well. They rarely swim, despite having webbed feet, usually landing on water only to bathe.[5]
The majority of sea terns have light grey or white body plumage as adults, with 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, the black tern, white-winged tern, and black-bellied tern, have black underparts in the breeding season. The Anous noddies have dark plumage with a pale head cap. 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.[8] Plumage type, especially 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.[9]
Juvenile terns typically have brown- or yellow-tinged upperparts, and the feathers have dark edges that give the plumage 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 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.[10]
Voice
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 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.[11] Parents and chicks can locate one another by call,[12] and siblings also recognise each other's vocalisations from about the twelfth day after hatching, which helps to keep the brood together.[13][14]
Vocal differences reinforce species separation between closely related birds such as the least and little terns,[15] and can help humans distinguish similar species, such as common and Arctic terns, since flight calls are unique to each species.[16][17]
Taxonomy
The bird
Following
The word "stearn" was used for these birds in
Species
The cladogram shows the relationships between the tern genera, and the currently recognised species, based on mitochondrial DNA studies, are listed below:[9]
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Based on Bridge et al (2005)[9] |
Image | Genus | Species |
---|---|---|
noddies
|
| |
Gygis Wagler, 1832 — noddies |
| |
Onychoprion Wagler, 1832 — brown-backed terns |
| |
Sternula F. Boie, 1822 — little white terns |
| |
Phaetusa — large-billed terns
|
| |
Hydroprogne Kaup, 1829— Caspian terns
|
| |
Gelochelidon Brehm, 1830 — gull-billed terns |
| |
Larosterna — Inca terns
|
| |
Chlidonias Rafinesque, 1822 — marsh terns |
| |
Thalasseus F. Boie, 1822 — crested terns |
| |
Sterna Linnaeus, 1758 — large white terns |
|
In addition to extant species, the fossil record includes a Miocene palaeospecies, Sterna milne-edwardsii.[40]
The genera Anous, Procelsterna and Gygis are collectively known as noddies, the Chlidonias species are the marsh terns,[5] and all other species comprise the sea terns.[41][42]
Distribution and habitat
Terns have a worldwide distribution, breeding on all continents including Antarctica. The northernmost and southernmost breeders are the Arctic tern and
Most terns breed on open sandy or rocky areas on coasts and islands. The
Behavior
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 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.
Breeding
Terns are normally monogamous, although trios or female-female pairings have been observed in at least three species.[5][46] Most terns breed annually and at 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 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.[5] Large tern species tend to form larger colonies,[17] 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 the cryptic plumage of the eggs and young for protection.[5]
The male selects a
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.[5] The eggs of most gulls and terns are brown
with dark splotches, so they are difficult for predators to spot on the beach.
Feeding
Most terns hunt fish by diving, often hovering first, and the particular approach technique used can help to distinguish similar species at a distance.[51] 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 the plough or hunting on foot on mudflats.[5] 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.[52] An individual tern's foraging efficiency increases with its age.[17]
The gull-billed tern is an opportunist predator, taking a wide variety of prey from marine, freshwater and terrestrial habitats. Depending on what 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.[53][54][55] 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.[56]
The eyes of terns cannot
-
Little tern in flight showing the forked tail
-
The gull-billed tern will sometimes prey on the chicks and young of other terns
-
The whiskered tern is an insect-eating marsh tern
Predators and parasites
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 the habitat, including rabbits, goats and pigs.[5] 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.[62]
Adult terns may be hunted by owls and raptors, and their chicks and eggs may be taken by herons, crows or gulls.[5][53] Less obvious nest predators include ruddy turnstones in the Arctic, and gull-billed terns in little tern colonies.[53][63] Adults may be robbed of their catch by avian kleptoparasites such as frigatebirds, skuas, other terns or large gulls.[5][64]
External parasites include chewing lice of the genus Saemundssonia,[65] feather lice and fleas such as Ceratophyllus borealis.[66] Lice are often host specific, and the closely related common and Arctic terns carry quite different species.[67] Internal parasites include the crustacean Reighardia sternae, and tapeworms such as Ligula intestinalis and members of the genera Diphyllobothrium and Schistocephalus.[68] 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.[69] In 1961 the common tern was the first wild bird species identified as being infected with avian influenza, the H5N3 variant being found in an outbreak involving South African birds.[70] Several species of terns have been implicated as carriers of West Nile virus.[71]
Relationships with humans
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 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 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.[5][72]
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 the birds could lead them to fish shoals.
Habitat enhancements used to increase the breeding success of terns include floating nest platforms for black, common and Caspian terns,[73][74][75] and artificial islands created for a number of different species.[76][77] More specialised interventions include providing nest boxes for roseate terns, which normally nest in the shelter of tallish vegetation,[78] and using artificial eelgrass mats to encourage common terns to nest in areas not vulnerable to flooding.[79]
Conservation status
A number of terns face serious threats, and the
The
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 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, the Cayenne tern, in the Caribbean.[5]
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.[88][89] 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.[90] The North American legislation is similar, although there is a greater emphasis on protection.[91]
See also
References
- ^ Maehr & Kale (2005) p. 111.
- ^ Olsen & Larsson (1995) p. 136.
- ^ Harrison (1988) p. 368.
- ^ Olsen & Larsson (1995) p. 25.
- ^ a b c d e f g h i j k l m n o p q r s t u v Gochfeld & Burger (1996) pp. 624–645.
- ^ a b c Harrison (1988) pp. 387–390.
- ^ Hutton & Drummond (2011) p. 226.
- ^ Simmons, Keith E L (1972). "Some adaptive features of seabird plumage types". British Birds. 65 (11): 465–479.
- ^ S2CID 25027599.
- ^ Olsen & Larsson (1995) pp. 6–9.
- ^ Hume (1993) pp. 68–75.
- ^ Burton (1985) p. 123.
- JSTOR 4087337.
- S2CID 4181980.
- JSTOR 4085004.
- ^ Constantine (2006) pp. 73–77.
- ^ a b c d e f Burger J; Gochfeld M "Laridae, Sternidae and Rynchopidae" in Steele et al. (2001) p. 1469–1480.
- PMID 13678682.
- .
- ^ a b c Hume (1993) pp. 12–13.
- ^ Linnaeus (1758) p. 84.
- ^ Jobling (2010) p. 338.
- ISBN 0-550-10105-5..
- S2CID 84758271.
- ^ PMID 16531074.
- PMID 15329156.
- ^ Moynihan, M (1959). "A revision of the family Laridae". American Museum Novitates (1928): 1–42.
- ^ a b Collinson, M (2006). "Splitting headaches? Recent taxonomic changes affecting the British and Western Palaearctic lists" (PDF). British Birds. 99 (6): 306–323.
- PMID 15012936.
- ^ Jobling (2010) p. 365.
- ^ Lockwood (1984) pp. 147, 153.
- ^ "Tern". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- ^ Merriam-Webster (2014)
- ^ "Sterna". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- ^ Turner (1544), p. 78.
- ^ Linnaeus (1758) p. 155.
- ^ a b Harrison (1988) p. 382.
- ^ a b "Black-fronted Tern Sterna albostriata". Species. BirdLife International. Retrieved 8 May 2013.
- ^ Gill, Frank; Donsker, David, eds. (2019). "Sandpipers, snipes, coursers". World Bird List Version 9.2. International Ornithologists' Union. Retrieved 25 June 2019.
- ^ "Fossil record of the Charadriiformes". Palaeobiology and Biodiversity Research Group, University of Bristol. Archived from the original on 4 March 2016. Retrieved 13 May 2013.
- ^ Barlow et al. (1987) p. 212.
- ^ Perrins & Arlott (1987) p. 130.
- ^ Harrison (1988) pp. 370–371.
- ^ Newton (2010) pp. 150–151.
- PMID 20080662.
- S2CID 85678067.
- ^ Watling (2003) pp. 206–207.
- ^ a b "Inca Tern Larosterna inca". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "The White Tern Gygis alba (Sparrman, 1786)" (PDF). Threatened Species Information. New South Wales National Parks and Wildlife Service. Archived from the original (PDF) on 5 August 2008. Retrieved 15 May 2013.
- ^ Olsen & Larsson (1995) p. 10.
- ^ Hume & Pearson (1993) pp. 54–55.
- ^ Svensson et al. (2009) p. 206.
- ^ a b c "Little tern". Queensland Government Department of Environment and Heritage Protection. Archived from the original on 10 March 2014. Retrieved 13 May 2013.
- JSTOR 1521644.
- S2CID 85996773.
- .
- ^ a b Coles (2007) p. 30.
- ^ a b Sinclair (1985) pp. 88–100.
- ^ Varela, F J; Palacios, A G; Goldsmith T M "Color vision in birds" in Ziegler & Bischof (1993) pp. 77–94.
- ^ Lythgoe (1979) pp. 180–183.
- PMID 17148194.
- ^ Hume (1993) pp. 112–119.
- ^ Parkes, K C; Poole, A; Lapham, H (1971). "The Ruddy Turnstone as an egg predator" (PDF). Wilson Bulletin. 83: 306–307.
- ^ Harrison (1988) pp. 320–323.
- .
- ^ Rothschild & Clay (1953) p. 82, 130.
- ^ Rothschild & Clay (1953) p. 135.
- ^ Rothschild & Clay (1953) p. 194–197.
- PMID 22035144.
- S2CID 7795090.
- ^ Takken & Knols (2007) p. 137–140.
- ^ Spennemann, Dirk H R (1999). "Exploitation of bird plumages in the German Mariana Islands" (PDF). Micronesica. 31 (2): 309–318. Archived from the original (PDF) on 27 June 2010.
- .
- JSTOR 1521499.
- JSTOR 1521819.
- .
- JSTOR 1522218.
- ^ Morrison, P; Gurney M (2007). "Nest boxes for roseate terns Sterna dougallii on Coquet Island RSPB reserve, Northumberland, England". Conservation Evidence. 4: 1–3.
- ^ Palestis, Brian G (2009). "Use of artificial eelgrass mats by saltmarsh-nesting Common Terns (Sterna hirundo)" (PDF). In Vivo. 30 (3): 11–16.
- ^ "Chinese Crested Tern Sterna bernsteini". Species. BirdLife International. Retrieved 7 May 2013.
- ^ "Black-bellied Tern Sterna acuticauda". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Peruvian Tern Sterna lorata". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Fairy Tern Sterna nereis". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Kerguelen Tern Sterna virgata". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Elegant Tern Sterna elegans". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "River Tern Sterna aurantia". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Damara Tern Sterna balaenarum". Species. BirdLife International. Retrieved 8 May 2013.
- ^ "Annex 2: Waterbird species to which the Agreement applies" (PDF). Agreement on the conservation of African-Eurasian migratory Waterbirds (AEWA). UNEP/ AEWA Secretariat. Archived from the original (PDF) on 28 July 2011. Retrieved 25 January 2012.
- ^ "List of Migratory Birds". Birds protected by the Migratory Bird Treaty Act. US Fish and Wildlife Service. Retrieved 25 January 2012.
- ^ "Introduction". African-Eurasian Waterbird Agreement. UNEP/ AEWA Secretariat. Archived from the original on 11 February 2012. Retrieved 25 January 2012.
- ^ "Migratory Bird Treaty Act of 1918". Digest of Federal Resource Laws of Interest to the U. S. Fish and Wildlife Service. U. S. Fish and Wildlife Service. Retrieved 25 January 2012.
Cited texts
- Barlow, Clive; Wacher, Tim; Disley, Tony (1997). A Field Guide to Birds of The Gambia and Senegal. Robertsbridge: Pica Press. ISBN 1-873403-32-1.
- Burton, Robert (1985). Bird Behaviour. London: Granada Publishing. ISBN 0-246-12440-7.
- Constantine, Mark; The Sound Approach (2006). The Sound Approach to birding: a guide to understanding bird sound. Poole: The Sound Approach. ISBN 90-810933-1-2.
- Coles, Brian (2007). Essentials of Avian Medicine and Surgery. Oxford: Wiley. ISBN 978-1-4051-5755-1.
- Gochfeld, M.; Burger, J. (1996). "Family Sternidae (Terns)". In del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.). Handbook of Birds of the World. Vol. 3: Hoatzin to Auks. Barcelona: Lynx Edicions. pp. 624–667. ISBN 978-84-87334-20-7.
- Harrison, Peter (1988). Seabirds: An Identification Guide. London: Christopher Helm. ISBN 0-7470-1410-8.
- Hume, Rob (1993). The Common Tern. London: Hamlyn. ISBN 0-540-01266-1.
- Hume, Rob; Pearson, Bruce (1993). Seabirds. London: Hamlyn. ISBN 0-600-57951-4.
- Hutton, Frederick Wollaston; Drummond, James (2011) [1904]. The animals of New Zealand: an account of the dominion's air-breathing vertebrates (reprint ed.). Cambridge: Cambridge University Press. ISBN 978-1-108-04002-0.
- Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names (PDF). London: Christopher Helm. ISBN 978-1-4081-2501-4.
- Linnaeus, C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata (in Latin). Holmiae [Stockholm]: Laurentii Salvii.
- Lockwood, W B (1984). Oxford Book of British Bird Names. Oxford: ISBN 0-19-214155-4.
- Lythgoe, J N (1979). The Ecology of Vision. Oxford: Clarendon Press. ISBN 0-19-854529-0.
- Maehr, David S; Kale, Herbert W (2005). Florida's Birds. Sarasota: Pineapple Press. ISBN 1-56164-335-1.
- Merriam-Webster (2014). "Tern - Definition and More from the Free Merriam-Webster Dictionary". Encyclopædia Britannica. Retrieved 11 January 2014.
- Newton, Ian (2010). Bird Migration (Collins New Naturalist Library 113). London: Collins. ISBN 978-0-00-730732-6.
- Olsen, Klaus Malling; Larsson, Hans (1995). Terns of Europe and North America. London: Christopher Helm. ISBN 0-7136-4056-1.
- Perrins, Christopher M; Arlott, Norman (1987). New generation guide to the birds of Britain and Europe. Austin: University of Texas Press. ISBN 0-292-75532-5.
- Rothschild, Miriam; Clay, Theresa (1953). Fleas, Flukes and Cuckoos. A study of bird parasites. London: Collins.
- Sinclair, Sandra (1985). How Animals See: Other Visions of Our World. Beckenham, London: Croom Helm. ISBN 0-7099-3336-3.
- Steele, John H; Thorpe Steve A; Turekian, Karl K, eds. (2001). Encyclopedia of Ocean Sciences. London: Academic Press. ISBN 978-0-12-227430-5.
- Svensson, Lars; Mullarney, Killian; Zetterstrom, Dan; Grant, Peter (1999). Collins Bird Guide. London: Collins. ISBN 0-00-219728-6.
- Takken, Willem; Knols, Bart G J, eds. (2007). Emerging pests and vector-borne diseases in Europe. Wageningen: Wageningen Academic Publishers. ISBN 978-90-8686-053-1.
- Turner, William. Evans, A H (ed.). Turner on Birds (Auium præcipuarum, quarum apud Plinium et Aristotelem mentio est, breuis et succincta historia) (1903 ed.). Cambridge: Cambridge University Press. Retrieved 11 January 2014.
huius generis est & alia parua auis, nostrati lingua sterna apellata 'There is another small bird of this type, called Stern in local dialect'
- ISBN 982-9030-04-0.
- Ziegler, Harris Philip; Bischof, Hans-Joachim, eds. (1993). Vision, Brain, and Behavior in Birds: A comparative review. Cambridge: MIT Press. ISBN 0-262-24036-X.
External links
- Tern videos on the Internet Bird Collection