Animal
Arctic tern
The Arctic tern is a small seabird. Every year it flies a very long way. It spends summer in the far north, then flies far south.
The Arctic tern is a small, graceful seabird with a black cap, a red bill and red legs. Every year it flies from its nesting grounds in the Arctic to the edge of the ice around Antarctica and back again. Scientists who tracked terns from Greenland and Iceland found that they flew an average of 70,900 kilometers in one year.
Sterna paradisaea breeds around the high latitudes of the Northern Hemisphere and winters in the Southern Ocean at the Antarctic ice edge. Geolocator tracking published in 2010 measured an average annual round trip of 70,900 kilometers for 11 birds from Greenland and Iceland, a study its authors titled 'longest animal migration'. The IUCN lists the species as Least Concern but decreasing (2018).
Photo: W. Bulach, CC BY-SA 4.0, via Wikimedia Commons
Meet the Arctic tern
The Arctic tern is a small gray and white seabird.
In summer it has a black cap, a red bill and short red legs. Its tail has two long, thin points.
The Arctic tern is a small, slender seabird, 28 to 39 centimeters long and only 90 to 120 grams, about as light as a small apple. Its wings are long and pointed and stretch 65 to 75 centimeters.
In the breeding season adults are pale gray with a full black cap, a red bill and short red legs. In winter the forehead turns white and the bill and legs turn black. Arctic terns fly gracefully and often hover in the air before diving for food.
Sterna paradisaea is a slender tern in the gull, tern and skimmer family, Laridae. Cornell gives a length of 28 to 39 centimeters, a mass of 90 to 120 grams and a wingspan of 65 to 75 centimeters.
Breeding adults are pale gray above and below with a full black cap extending down the nape, a red bill and red legs. Nonbreeding birds show a white forehead, a smaller cap, a black bill and legs and a dark carpal bar. Cornell notes that Arctic terns hover above feeding areas and colonies more often than the similar common tern.
Quick facts
- Group
- Bird
- Length
- 0.28 to 0.39 m
- Wingspan
- 0.65 to 0.75 m
- Weight
- 0.09 to 0.12 kg
- Lifespan in the wild
- up to 34 years
A bird of two poles
Arctic terns nest in the far north in summer.
Then they fly all the way to the far south, near Antarctica. There it is summer too!
Arctic terns nest across the Arctic, in open places with few or no trees, on small islands and on beaches. Breeding countries include Canada, the United States, Greenland, Iceland, Norway, Sweden, Finland, the United Kingdom and Russia.
When the northern summer ends, they fly south over the Atlantic and Pacific Oceans to the edge of the pack ice around Antarctica, where it is summer. So an Arctic tern sees two summers every year.
The species breeds in a circumpolar band at high northern latitudes. The IUCN's 2018 global assessment lists breeding in Greenland, Iceland, Norway, Svalbard, the Faroe Islands, Russia, the United Kingdom, the Baltic states, the Netherlands, Belgium and the United States, with other northern countries such as Canada, Denmark, Finland, Germany, Ireland and Sweden also coded as extant.
Cornell describes breeding habitat as treeless areas with little cover, open boreal forest, and islands and barrier beaches in the northeastern Atlantic. Birds migrate offshore over the Atlantic and Pacific and spend the austral summer at the Antarctic pack-ice edge.
Continents
Where can you find this animal?
- Migration route · Countries and seas named by a scientific source
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
- Visits for part of the year · Countries and seas named by a scientific source
Migration route · Countries and seas named by a scientific source
Migration routes over the open ocean. Tracked birds from Greenland and Iceland stopped in the North Atlantic, then flew south along either the West African or the Brazilian coast; three went east into the Indian Ocean. North American birds also migrate over the Pacific (Cornell Lab).
Places: Atlantic Ocean, Pacific Ocean and Indian Ocean.
Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC2836663/ · checked October 2026
Lives here naturally · Countries and seas named by a scientific source
Breeding range: coasts, islands and open, treeless ground around the Arctic and the northern Atlantic, from northern North America to Greenland, Iceland, northern Europe and Russia. The Faroe Islands and Svalbard are also breeding areas but have no separate map shape.
Places: Canada, United States, Greenland, Iceland, Norway, Sweden, Finland, Denmark and 10 more places.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in Sweden, United States, Finland, Denmark, Norway, Iceland, UK, Canada and 94 more places.
Source: gbif · checked October 2026
Visits for part of the year · Countries and seas named by a scientific source
Non-breeding season (the southern summer, about December to March): the edge of the pack ice around Antarctica. Tracked birds from Greenland and Iceland wintered south of 58° S in the Atlantic sector, including the Weddell Sea.
Places: Antarctica and Southern Ocean.
Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC2836663/ · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
What it eats
Arctic terns eat small fish.
They hover in the air, then dive down to grab a fish. They catch bugs too.
Arctic terns eat small fish, usually less than 15 centimeters long, such as sand lances, sand eels, herring, cod and smelt. They also snatch insects from the air or the surface of the water.
A tern hovers over the water, then plunges in, but only about 50 centimeters deep, and comes up with a shake. Gulls and jaegers often try to steal its catch. On migration terns sometimes feed with other seabirds where big fish push small fish to the surface.
The diet consists mainly of small fish, generally under 6 inches (15 centimeters), including sand lances, sand eels, herring, cod and smelt, plus insects; the tracking paper describes the diet as mainly small fish and large zooplankton.
Terns surface-dip or plunge to about 20 inches (50 centimeters), then rise with a shake and swallow the fish head first. They are frequent targets of kleptoparasites such as jaegers and gulls. On migration they often forage with other seabirds over schools of predatory fish that drive prey to the surface.
A light, long-winged flier
Arctic terns are light, with long wings.
They can fly for a very long time. They often rest on floating ice.
For such a long traveler, the Arctic tern is tiny: lighter than a cup of water, with long, narrow wings and a long, pointed tail. It flies with light, rowing wingbeats over open water.
The tracking study found that terns follow the world's big wind patterns, which helps them save energy. During their winter near Antarctica, which is the southern summer, they grow new wing feathers, and while this happens they rarely fly, resting instead on small blocks of ice at the edge of the pack ice.
Despite weighing under 125 grams, the Arctic tern makes a migration that the tracking authors say may be the longest seasonal movement of any animal; their paper's title calls it the longest animal migration. Their routes showed that terns exploit the prevailing global wind systems, clockwise in the North Atlantic and counterclockwise in the South Atlantic, to reduce flight costs.
Cornell describes buoyant, graceful flight with rowing wingbeats and frequent hovering. During the wing molt in the austral summer the birds rarely fly and spend much of their time resting on small floes at the edge of the pack ice.
Growing up
Arctic terns lay their eggs on the ground.
The chicks are fluffy and can walk, but they stay in the nest.
Arctic terns nest on the ground near water, in a simple scrape on rocks, sand or short grass. The female lays 1 to 3 speckled olive or buff eggs, and they hatch after 21 to 23 days.
The chicks hatch covered in fluffy down with their eyes open, and they can walk, but they stay in the nest. They fledge, leaving the nest, after 21 to 28 days. Young terns do not start breeding until they are 3 or 4 years old, and some live for decades.
Both members of the pair make a scrape on rocky or sandy ground near water and may add grass or pebbles to the rim. The clutch is 1 to 3 olive to buff eggs with dark spots; incubation lasts 21 to 23 days and the nestling period 21 to 28 days.
Hatchlings are downy with open eyes and able to walk; Cornell notes that chicks from the same nest can be gray or brown. Pairs are monogamous for the breeding season. Birds usually first breed at 3 or 4 years, and the oldest recorded Arctic tern was at least 34 years old when recaptured in Maine.
Fish gifts and fierce parents
To find a partner, a male tern flies with a fish in his bill.
Tern parents guard their nests. They call loudly and swoop at anyone who comes near their nest.
Arctic terns nest in noisy colonies. In courtship, a male flies low over the colony carrying a fish to catch a female's attention, and later he feeds her fish as the pair bond grows.
Tern parents defend their nests fiercely. They chase away other birds, and if people walk into a colony, the terns dive toward them and may peck their heads. If you ever visit a tern colony, stay on the path and keep your distance.
The species is gregarious and breeds in noisy colonies. Courtship includes a fish flight, in which the male flies low over the colony with a fish held bill-down and an interested female follows; on the ground the male postures with head down and wings held out, then courtship-feeds the female.
Nest defense escalates from a bent posture, head down with wings held out, to an upward-pointing bill and finally attack, with birds fencing with their bills. Cornell notes that terns dive at people entering a colony and may peck their heads.
Did you know?
One tracked tern flew more than twice around the world in a year.
The farthest-flying tracked tern covered 81,600 kilometers in a year, about twice the distance around the Earth.
Tracked distances ranged from 59,500 to 81,600 kilometers a year, with a mean of 70,900 kilometers.
Arctic terns today
There are lots of Arctic terns.
People keep their nesting places safe and quiet. Long ago people hunted them for their feathers, but that stopped.
The Arctic tern is listed as Least Concern, and Partners in Flight estimates there are about 3 million breeding birds. But numbers seem to be going down, and because terns live in remote places, scientists find them hard to count.
In the late 1800s terns were hunted for the feather trade. In North America a law passed in 1918 protected them, and most populations recovered. Today disturbance at colonies, damage to nesting beaches and fewer fish are concerns.
The IUCN's 2018 global assessment lists Sterna paradisaea as Least Concern with a decreasing trend. Partners in Flight estimates about 3 million breeding birds, while the North American Waterbird Conservation Plan lists it as a species of high conservation concern; Cornell notes that the birds' Arctic distribution makes trends hard to estimate.
The feather trade caused declines in the late nineteenth century, and most populations recovered after the US Migratory Bird Treaty Act of 1918. Potential threats now include human disturbance at colonies, degradation of barrier-beach and island nesting habitat and reduced fish stocks.
IUCN Red List
How is the arctic tern doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
See the IUCN Red List assessment · The IUCN Red List of Threatened Species 2021.3
Amazing facts
-
Arctic terns see two summers every year.
Arctic terns spend the northern summer in the Arctic and the southern summer near Antarctica, so they see two summers every year.
Breeding in the boreal summer and wintering at the Antarctic ice edge in the austral summer, Arctic terns spend much of the year in polar daylight.
-
One tracked tern flew more than twice around the world in a year.
The farthest-flying tracked tern covered 81,600 kilometers in a year, about twice the distance around the Earth.
Tracked distances ranged from 59,500 to 81,600 kilometers a year, with a mean of 70,900 kilometers.
-
Tern chicks can be gray or brown.
Fluffy Arctic tern chicks come in two colors, gray or brown, and chicks in the same nest are not always the same color.
Downy hatchlings are gray or brown, and broods can be mixed.
-
The oldest Arctic tern known was at least 34 years old.
The oldest Arctic tern on record was at least 34 years old when it was caught and released again in Maine.
Cornell reports a longevity record of at least 34 years, from a bird recaptured during banding in Maine.
Words to know
- migration
- a regular journey animals make between places, often with the seasons
- geolocator
- a tiny device that records light levels so scientists can work out where an animal has been
- stopover
- a place where migrating animals rest and feed partway through their journey
- colony
- a large group of animals that live and breed together
- pack ice
- large areas of floating sea ice
- hover
- to stay in one place in the air by flapping
Discovery challenge
-
Where do Arctic terns go after their summer in the north?
Where do Arctic terns spend the northern winter?
Where did tracked Arctic terns spend the non-breeding season?
- Near Antarctica
- In a cave
- In a desert
Show the answer
Near Antarctica
They fly all the way to the ice near Antarctica.
They fly to the edge of the pack ice around Antarctica, where it is summer.
South of 58° S in the Atlantic sector of the Southern Ocean, including the Weddell Sea region.
-
How far did the tracked terns fly in a year?
About how far did tracked Arctic terns fly in one year, on average?
What mean annual migration distance did the 2010 tracking study measure?
- About 700 km
- About 7,000 km
- About 70,900 km
Show the answer
About 70,900 km
About 70,900 kilometers: an enormous trip!
On average 70,900 kilometers, and one bird flew 81,600.
70,900 kilometers on average (range 59,500 to 81,600) for 11 birds from Greenland and Iceland.
-
What color is an Arctic tern's bill in summer?
What color are an Arctic tern's bill and legs in the breeding season?
Which bare-part color marks breeding-plumage Arctic terns?
- Red
- Blue
- Green
Show the answer
Red
Its bill is red in summer.
Red, along with a full black cap; in winter they turn black.
Red bill and legs, which become black in nonbreeding plumage.
-
What do Arctic terns eat?
What is the main food of Arctic terns?
Which prey makes up most of the Arctic tern's diet?
- Small fish
- Seeds
- Leaves
Show the answer
Small fish
They eat small fish, and some bugs.
Small fish such as sand eels and herring, plus some insects.
Mainly small fish, generally under 15 centimeters, and large zooplankton.
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For parents & teachers
What children will learn
- Describe the Arctic tern's yearly migration between the Arctic and Antarctica.
- Explain how scientists used tiny trackers to measure the migration.
- Describe the tern's appearance, food and breeding.
- Explain why tern colonies need protection from disturbance.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might a bird fly so far to spend the southern summer near Antarctica?
- How might wind help or hinder a small bird on a long journey?
- What might people do to keep a tern colony safe?
Try at home or in class
- On a globe, trace a route from Greenland to Antarctica and back with string, then measure the string.
- Weigh a small apple (about 100 grams) and imagine carrying that much body across the world.
Key vocabulary: migration, geolocator, stopover, colony, pack ice, hover
Where these facts come from
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Sterna paradisaea (Arctic Tern), Red List global assessment 2018 , IUCN Red List of Threatened Species
- Tracking of Arctic terns Sterna paradisaea reveals longest animal migration (Egevang et al. 2010, PNAS) , PubMed Central, US National Library of Medicine
- Arctic Tern overview , Cornell Lab of Ornithology, All About Birds
- Arctic Tern life history , Cornell Lab of Ornithology, All About Birds
- Arctic Tern identification , Cornell Lab of Ornithology, All About Birds
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated October 28, 2026. Spotted a mistake? Tell us.