Sterna paradisaea

The Arctic Tern (Sterna paradisaea) is perhaps best known for its extraordinary annual migration, which is often cited as the longest seasonal distance traveled by any animal. It has long been known that the Arctic Tern breeds in the Arctic and migrates each year to spend the northern winter at high latitudes in the Southern Ocean. Until recently, what has been known about the Arctic Tern's migration has come from limited banding recoveries and at-sea observations. Thanks to new technology, however, far more detailed data on this small (<125 grams) bird's annual migration are now available. Egevang et al. (2010) fitted 11 Arctic Terns with miniature (1.4 gram) geolocators. They found that the annual distances traveled are, in fact, even greater than previously believed--more than 80,000 km annually for some individuals. All tracked terns migrated south to spend the austral summer (December–March) south of 58° S and between 0 and 61° W in the Atlantic sector of the Southern Ocean. This region, which includes the Weddell Sea, is particularly productive, and supports higher densities of a key prey for many seabirds, Antarctic krill (Euphausia superba), than do other regions of the Southern Ocean. All birds began the return migration to breeding colonies in early–mid April, always traveling over deep water at considerable distance from continental shelf margins.

Egevang et al. note that the routes used for both the southbound and northbound migrations showed a high level of congruence with parts of those taken by Manx Shearwater (Puffinus puffinus) and Cory’s Shearwater (Calonectris diomedea), which also winter in the South Atlantic (although considerably farther north than the Arctic Tern). Thus, despite their small size, Arctic Terns apparently exploit the prevailing global wind systems (clockwise in the North, and counter-clockwise in the South Atlantic) much as the substantially larger shearwaters do, as has been previously suggested. These new geotracking studies found that the main wintering region was the marginal ice zone around Antarctica, which agrees with at-sea observations. The mean duration of the northbound migration was about 40 days (range 36 to 46). Mean duration of the southbound migration was about 93 days (range 69 to 103). (Egevang et al. 2010)

Egevang et al. (2010) provide the following summary of key statistics derived from their study, showing mean (range):

Total distance traveled on migration: 70,900 km (59,500–81,600 km)
Distance traveled on southbound migration: 34,600 km (28,800–38,500 km)
Distance traveled per day on southbound migration: 330 km per day (280–390 km per day)
Distance traveled on northbound migration: 25,700 km (21,400–34,900 km)
Distance traveled per day on northbound migration: 520 km per day (390–670 km per day)
Distance traveled within winter site: 10,900 km (2,700–21,600 km)

Perhaps most striking, the tracked birds were found to travel nearly twice the total distance generally cited for the annual Arctic Tern migration (typically quoted as ~ 40,000 km). Given that Arctic Terns can live for more than 30 years, the total distance traveled in a lifetime may exceed 2.4 million km, equivalent to approximately three round-trip journeys to the Moon. (Egevang et al. 2010)

Arctic terns are the champion of all migrating birds. They migrate the furthest south to overwinter, as far as the South Pole ice. In the spring, they return to their breeding grounds in the North Sea area or further northwards. In total, they make an annual trip of around 35,000 kilometers per year! A young Arctic tern supplied with a transmitter in Groningen in the summer of 2011 flew at least 90,000 kilometers in 273 days. If you realize that Arctic terns can reach an age of 30 years and make this trip every year, than this tern possibly flies more than 2.7 million km in its entire life. That is equivalent to approximately 3 return trips to the moon!

The Arctic tern is a long-distance migrant, making a staggering annual round-trip from its Arctic or northern temperate breeding range to the Antarctic where it spends winter (3). This is probably the longest migration undertaken by any bird (2) and means that the Arctic tern sees more sunlight each year than any other animal, as they experience a 'second summer' by travelling south in winter (5). They are very similar in appearance to the common tern (Sterna hirundo), so much so that birdwatchers call unidentified terns 'commic terns', an amalgamation of the two common names (6). Arctic terns are slightly smaller than common terns, and have a shorter bill and longer tail (2). The rump is white, the underparts are darker and the wing lacks the dark wedge on the outer edge, which is a key identifying feature of common terns (6) . During summer, the bill becomes bright red and lacks the black tip seen in common terns (2). Long tail streamers also develop in summer (2). A 'kee-arr' alarm call and a piping 'pi-pi-pi-pi-pi' call are produced (2) (6).

The Arctic tern tends to arrive back in its breeding habitats after the long migration from May to June (3). Males court females with a 'fish flight', an impressive aerial display which culminates in the male presenting the female with a 'gift' in the form of a fish (6). Nesting tends to occur in a hollow on the ground at a good distance from the shore in short vegetation (4) (6). Pairs, which mate for life, produce between one and three eggs, which are incubated for up to 24 days (3) (6). After a further 24 days or so, the chicks will have fully fledged. The males defend the nests if they are threatened, by diving at potential predators and livestock (6).  Arctic terns are very long-lived species, with a maximum recorded life-span of 29 years (3). This species feeds mainly on fish, particularly sand eels (3) (4), which they catch by making short dives into the water (6). Feeding tends to occur within 3 km of the breeding colony, although they have been recorded to travel 10 km away in order to feed (4). When the breeding season is over, these birds head off once more on their long journey south (3).

Arctic circumpolar; winters sub-Antarctic and Antarctic seas.

Belgian Exclusive Economic Zone, European waters (ERMS scope), Gulf of Maine, Gulf of Mexico, Iceland, Irish Exclusive economic Zone, Mozambique, New Zealand Exclusive Economic Zone, North West Atlantic, Northern Hemisphere, Polish Exclusive Economic Zone, Portuguese Exclusive Economic Zone, Sandy Island, Somalia, South Africa (country), Spanish Exclusive Economic Zone, Swedish Exclusive Economic Zone, United Kingdom Exclusive Economic Zone, Wimereux

North America; Oceania; range extends from the Arctic to the Bay of Fundy region

The Arctic Tern has a circumpolar range, breeding in the Arctic and subarctic regions of Europe, Asia and North America as far south as Brittany, France and Massachusetts (USA). It is a transequatorial migrant, and can be found wintering throughout the Southern Ocean to the edge of the Antarctic ice and the southern tips of South America and Africa¹. Overall population trends are relatively unknown, though the 2008 breeding season in the north of the United Kingdom was reported to be a failure by the RSPB.

Circumpolar; nests on Northern European islands and peninsulas from Iceland to Northern Russia/Siberia, British Isles, Netherlands, Denmark, Sweden, the Baltic Nations, Northern Alaska, extreme of Northern Canada, Greenland, Newfoundland, and south along Atlantic Coast to Massachussetts; winters in S. Hemisphere in subantarctic and Antarctic waters of Atlantic, Pacific, and Indian Oceans.

Biogeographic Regions: nearctic (Native ); palearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Breeding range extends from northern Alaska east to northern Ellesmere Island, south to the Aleutian Islands, northwestern British Columbia, northwestern Saskatchewan, northern Ontario, New Brunswick, and along Atlantic coast, locally to Maine and Massachusetts; a disjunct colony exists in Puget Sound, Washington, and solitary nesters in northcentral Montana. Outside North America, nesting occurs in Greenland on all coasts; in the Palearctic north to Iceland, Svalbard, and Franz Josef Land, and south to the Netherlands and sparsely in Belgium, Ireland, and northwestern France; and in northern Russia and widely along Russian far eastern arctic coasts (Wrangel Island, Chukotska and Kamchatka Peninsulas south to Sakhalin Island) (Hatch 2002).

During the nonbreeding season, this species occurs primarily in the antarctic and subantarctic regions of the Southern Hemisphere, with small numbers reported throughout the year from Namibia to Mozambique, southern Australia, and New Zealand (Hatch 2002). Migrants occur widely in areas between the breeding areas and antarctic region.

Arctic terns breed around the Arctic and temperate northern parts of the northern Hemisphere. They travel massive distances to overwinter in the Southern Ocean and Antarctica (4). The population that breeds in Britain and Ireland is at the southern-most limit of its breeding range. This range extends through Greenland and Iceland, along the Baltic and Scandinavian coasts reaching into Siberia. Most of the British breeding population occurs in Scotland, Orkney, Shetland and the Hebrides. Populations also occur in England in the northwest and northeast and there are small numbers in Norfolk and around the southern coast; they also breed in Anglesey in Wales (4).

Arctic terns are 14-17''(36-43 cm) long with a wingspread of 29-33''(74-84 cm). They are white with black caps and gray mantles, and a deeply-forked tail. In spring and summer, the entire bill is blood-red. Their legs are so short that the birds appear to be crouched when standing.

Average mass: 100 g.

Length: 39 cm

Weight: 110 grams

Length: 33-41 cm. Plumage: tail, rump, back and wings pale grey, wingtips darker grey; hind neck white; forehean white, forecrown speckled white; below white; breeding bird has pearl grey below, cheeks white; deeply forked tail extends slightly beyond wing. Immature browner on back. Bare parts: iris dark brown; bill red in breeding and black in non-breeding birds; feet and legs red in breeding and black in non-breeding. Habitat: open ocean and seashores. Palearctic migrant. <389><391><393>

Habitat and Ecology

Systems

• Terrestrial
• Freshwater
• Marine

All terns live along seacoasts and around interior lakes and marshes.

Terrestrial Biomes: tundra ; taiga ; forest ; icecap

Aquatic Biomes: lakes and ponds; coastal

Depth range based on 2811 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1917 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): -1.542 - 24.813
  Nitrate (umol/L): 0.065 - 29.325
  Salinity (PPS): 6.428 - 36.842
  Oxygen (ml/l): 4.763 - 9.061
  Phosphate (umol/l): 0.086 - 2.073
  Silicate (umol/l): 1.179 - 70.561

Graphical representation

Temperature range (°C): -1.542 - 24.813

Nitrate (umol/L): 0.065 - 29.325

Salinity (PPS): 6.428 - 36.842

Oxygen (ml/l): 4.763 - 9.061

Phosphate (umol/l): 0.086 - 2.073

Silicate (umol/l): 1.179 - 70.561
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Comments: NON-BREEDING: mostly pelagic, rarely in coastal bays and estuaries. Migrates primarily at sea along coasts. BREEDING: Nests on ground on rocky, sandy, gravelly, or grass-covered coasts and islands, in far north on islands in lakes and ponds and in marshes and on riverine gravel bars, sometimes on open tundra (Terres 1980). See Spendelow and Patton (1988) for further details.

In Britain, this species breeds around the coast (4) in open sand or shingle habitats or in moorland and coastal heathland (3). As they are vulnerable to predation, they often breed on offshore islands areas where there are no mammal predators such as rats and mink (3). In winter this species stays out at sea, resting on floating objects and ice (3).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Arrives in breeding areas April-June (late May to mid-June in Beaufort Sea area), departs by August-September (Bent 1921). Migrates mainly well offshore.

Arctic terns hover 30-40 feet over the water on beating wings and then dive suddenly into the water with a splash, often completely submerging to catch small fishes such as capelin, sand launae, sand eel, and small crustaceans.

Comments: Eats small fishes and crustaceans obtained by diving from air into surface water.

Sterna paradisaea (Sterna paradisaea Arctic tern) preys on:
Sprattus sprattus
Clupea harengus
Anguilla anguilla
Ammodytes tobianus

Based on studies in:
Scotland (Estuarine)

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of nesting occurrences (subpopulations).

>1,000,000 individuals

Comments: Global breeding population is estimated at between 1 to 2 million pairs; includes primarily coastal estimates of about 12,800 pairs on the Atlantic U.S. coast; 80,000 pairs in Greenland; 200,000-500,000 pairs in Iceland; 72,000 pairs in Scotland; 70,000 pairs elsewhere in Atlantic Europe; 50,000 pairs in Baltic European countries; several hundred thousand in Russia; and several hundred thousand in Alaska (Lensink 1984, Hatch 2002). Few estimates exist for interior-nesting birds.

Visitor

Average lifespan
Status: wild: 408 months.

Maximum longevity: 34 years (wild) Observations: As with other terns, these animals are long-lived. No senescence has been demonstrated in the Artic tern (Roger Gosden 1996). A 34-year-old individual was released and appeared in excellent health (John Terres 1980).

They nest in colonies defended by the males in the rocky or sandy beaches of the far north. The nest usually consists of a hollow in sand, gravel or moss. In June-July, 2-3 brown or greenish eggs with brown speckles are incubated for 21-22 days. Young fly about 21-28 days after hatching

Average time to hatching: 21 days.

Average eggs per season: 2.

Lays clutch of 2-3 eggs, June-July. Incubation, by both sexes, 20-24 days. Young are tended by both parents, may leave nest soon after hatching but remain nearby, first fly at 20-23 days (then still fed by parents). Nests usually in small scattered colonies, in large dense colonies only at southern edge of range.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 9
Specimens with Barcodes: 14
Species With Barcodes: 1

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 9 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

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Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2009
  Least Concern
• 2008
  Least Concern
• 2004
  Least Concern

Foxes, raccoons, weasels, rats, gulls, and other seabirds are all predators of terns and their eggs. Massive spraying of marshes with insecticides (DDT) for mosquito control has killed many terns through their consumption of DDT-laden minnows. In the last decade of the 19th century and in the first decade of the present one, plume hunters killed tens of thousands of terns for their plumage for women's hats.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5B - Secure

United States

Rounded National Status Rank: N5B - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Secure: common, widespread, and abundant.

Included in the Birds of Conservation Concern Amber List (medium conservation concern) (3). Receives general protection in Great Britain under the Wildlife and Countryside Act and listed under Annex I of the EC Birds Directive. Listed as a Species of European Conservation Concern (4).

Population

Major Threats

Comments: This species is vulnerable to food shortages, predation (including egg predation by humans), pollution, and habitat degradation and loss (Howes and Montevecchi 1993). Disturbance at colony sites could cause desertion or declines (Howes and Montevecchi 1993), but terns have also shown potential for habituation to human activity under certain conditions. Growing gull populations have displaced terns from breeding habitat in some parts of Atlantic Canada and increased predation on young and eggs (Lock 1992). Climatic warming could decrease abundance or change distribution of ice-associated prey species such as the Arctic cod.

This species is listed on the Birds of Conservation Concern Amber List; its population has experienced periodic declines since the 1980s and low breeding success throughout the 1990s (4). Declines have also occurred elsewhere in Europe. The main threats facing this species include nest predation by hedgehogs, introduced American mink (Mustela vison) and rats, as well as coastal development, disturbance by recreational activities, and a lack of the most important food source, sandeels, possibly caused by over-fishing by humans (4).

Management Requirements: Gull control has been beneficial for this species in Maine (Buckley and Buckley 1984). See Minsky (1981) for discussion of tern management on Cape Cod.

Biological Research Needs: Very little is known about nonbreeders in the antarctic, where most of the mortality occurs. Better information is needed on wintering ecology in the southern hemisphere and threats to breeding populations in the northern hemisphere.

38% of the British breeding population occurs within Special Protection Areas (SPAs) and so the species receives a level of protection at these sites (4).

Once hunted for their feathers.

Comments: In Greenland, egg-collecting is an important source of mortality (Evans 1984a).

Least Concern