Arctic Tern
Arctic Tern Facts
| Size | 13-14 inches (33-36 cm) |
| Speed | 22-31 mph (35-50 km/h) |
| Weight | 3-4.5 ounces (86-127 grams) |
| Lifespan | 10-11 years |
| Food | Fish, krill, crustaceans |
| Predators | Seagulls, cats, rats, foxes |
| Distribution | Arctic circle, Antarctic circle |
| Habitat | Sea, coast, grassland, wetlands, mudflats |
| Order | Shorebirds |
| Family | Gulls |
| Scientific name | Sterna paradisaea |
| Characteristics | Small bird, doing the longest migration of all animals |
Main Characteristics
The arctic tern is a migratory bird. Of all animals in the world, it migrates the longest distance: more than 60,000 miles (96,000 km). It flies across the earth twice every year because it breeds in the Arctic Circle and winters in the Southern Arctic Circle.
Distribution and Habitat
Worldwide
Despite its name the arctic tern lives not only in the Arctic, but in the Antarctic, too. It spends the summer in the Arctic Circle near the North Pole to breed, staying in coastal areas most of the time. In winter it lives in the Antarctic Circle, on the edge of the pack ice zone, hunting fish and resting on ice. On its migrations from the Arctic to the Antarctic (and vice versa), it often visits grasslands, estuaries and wetlands such as mudflats.
In Germany
The arctic tern also lives partly in Germany. On the Baltic Sea it can often be seen in the Wismar Bay. They also exist in the North Sea: on the East Frisian Islands, on Scharhörn, on the "Halligen“ (= small marsh islands) named Hooge, Langeneß and Oland as well as on the coast of Schleswig-Holstein. About a third of the animals that migrate through Germany breed on the Halligen.
Way of Life
Arctic terns spend one-third of the year in the Arctic, another third in the Antarctic, and the remaining third traveling between the two poles. They are diurnal, gather in small colonies, breed and search for fish.
Anatomy and Appearance
Size and Weight
Arctic terns are around 13-14 inches (33-36 cm) from the tip of its beak to the end of its tail. Its wingspan is 33-33 inches (76-85 cm). Its weight is 3-4.5 ounces (86-127 grams).
Physique
The arctic tern is a very small bird. It has a long body but very short legs and a short beak compared to other terns.
Beak
The arctic tern's red beak is very long and narrow. It is perfectly adapted to the bird's hunting behavior. When it dives into the water, its narrow beak creates little resistance.
Feet
The Arctic tern's feet are deep red, as is its beak.
Arctic Tern or Common Tern – What's the Difference?
Arctic terns and common terns are closely related. They are very difficult to tell apart because they are similar in size and sport similar colors. The only aspect in which they differ significantly is the beak. The tip of the common tern's beak is black.
Diet
Arctic terns feed primarily on marine animals: fish, crustaceans, crabs and krill.
Behavior
Hunting Behavior
Arctic terns use their sharp eyes to scan the surface of the water for fish. Once they spot a fish, they nose-dive into the water at a steep angle to grab the prey. This hunting technique is called “plunge-diving”.
Defense Behavior
The arctic tern looks pretty and harmless, but it is very strong-willed and surprisingly aggressive in defending its chicks. It shows no hesitation in swooping down on people, targeting the back of their heads with its beak. Luckily, its beak is too tiny to inflict any serious harm. The impact of such an attack tends to be more surprising than anything else. However, it is better to stay away from the birds so as not to disturb them in their natural habitat. We are, after all, guests in their home and should act accordingly, treating it with the respect it deserves rather than intruding.
Migration Route
Arctic terns sometimes migrate along coasts, sometimes over the open sea and sometimes even over land. They have different flight routes - depending on their breeding site. The birds of northeastern Canada and northwestern Europe meet to fly south together. They then separate to fly along the coast of either South America or Africa. The birds of northwest America and northeast Asia instead fly along the west coast of America or over the sea. In the end all groups meet again in Antarctica. Here, we provide a migration map:
The Longest Migration
Tracking Via GPS
Of all animals in the world, the arctic tern holds the record for the longest migration. It can fly a distance of 60,000 miles (96,000 km) per year. The record for the longest flight was set in 2015-2016 by an animal using a tiny GPS tracker. Normally the animals only fly a distance of 18,000 miles (30,000 km) on average.
From the Farne Islands to Antarctica
The arctic tern, which set the breathtaking record of 60,000 miles (96,000 km), began its journey in July 2015. It started from the Farne Islands in north-east England. By August, it reached South Africa. It spent October in the Indian Ocean. In November it was in Antarctica and in February it arrived in the Weddell Sea. In April it was back in South Africa and in May 2016 it flew along the west coast back to the Farne Islands. For a small animal that weighs just around 3.5 ounces (100 grams) on average, this is a huge achievement.
Four Times to the Moon and Back
The Arctic tern, which has covered over 60,000 miles (96,000 km), could be flying as far as incredible two million miles (three million kilometers) in its life. That's what scientists calculated. The flight distance is about as long as going to the moon and back four times.
Adaptations for Survival
The Arctic tern is perfectly adapted to long migrations. Its small, streamlined body minimizes air resistance, as well as its short legs. With hollow bones, it remains lightweight, allowing it to navigate the wind effortlessly. This saves energy during flight. Additionally, the arctic tern is an exceptional flier; it can even close its eyes while soaring, catching some sleep as it glides through the sky.
Senses and Abilities
Flight Range
Arctic terns can fly up to 400 miles (670 km) in a single day. On average they fly a distance of 320 miles (520 km). A little support makes all the difference: tailwind! The birds are smart and use air currents to get to their destination as quickly as possible.
Sense of Sight
Arctic terns rely on their eyesight, which is their most important sense. They have exceptional vision, particularly in daylight. Since the sun remains above the horizon throughout the Arctic summer and the Antarctic winter, these birds can hunt almost around the clock.
Navigation
How do arctic terns find their way from the North Pole to the South Pole – and back? They navigate by using the coastlines and the Earth's magnetic field.
Life Expectancy
In the wild, Arctic terns live to be 10-11 years old.
Enemies and Threats
Natural Enemies
Arctic terns don’t have many enemies. However, during the breedings season its offspring are in severe danger. Great black-backed gulls, American herring gulls, European herring gulls and black-headed gulls as well as brown rats, cats and foxes raid the nests and steal the eggs.
Human Impact
Climate change and fishing is the greatest threat to the arctic tern. Fish often hide under ice not just from enemies, but also from the strong sunlight. The less ice there is, the more difficult it is for the fish to survive and the less food there is for the Arctic terns. Add in the fact, that fishing makes it even harder for them to find food. They have to adapt and move to different feeding areas. However, after their long journeys they are often very weak and starving.
How Can You Help Arctic Terns?
It's simple: eat less fish. We don't need fish to survive. Arctic terns do.
Conservation Status
Globally, arctic terns aren't (yet) threatened. There are over two million animals worldwide, with over a million in Europe alone. Unfortunately, there aren't a lot of them in Germany. The bird has been facing extinction risks since 2020, so if you spot one there, consider yourself lucky!
Importance for the Ecosystem
The arctic tern plays a key role in maintaining the fish population. It also highlights the extent of climate change we've experienced, which can guide us in taking the right actions.
Reproduction
Arctic terns stay together for one breeding season. The mating ritual is very romantic. The male offers the female fish to convince her of himself. The male continues to feed the female even after they mate, ensuring she stays healthy and that the eggs develop well. The pair works together to find the perfect spot for their nest and take turns incubating the eggs. After about 22-27 days, the chicks break free from their eggs, and they’re ready to take to the skies about 21-24 days after that. They get fed for a month or two before they learn how to catch their own food. By the time they are three months old, they’re pretty much independent.
The Arctic Tern Is Related To:
- Common Tern
- Scissorbill
Animals in the Same Biome:
- Adelie Penguin
- Albatross
- American Herring Gull
- Antarctic Fur Seal
- Antarctic Petrel
- Auk Birds
- Bearded Seal
- Beluga Whale
- Black-Backed Gull
- Blue Whale
- Bowhead Whale
- Brown Rat
- Canada Gull
- Chinstrap Penguin
- European Herring Gull
- Grebe
- Leopard Seal
- Macaroni Penguin
- Minke Whale
- Narwhal
- Orca
- Polar Bear
- Red Fox
- Ringed Seal
- Snowy Owl
- Walrus
- Weddell Seal
Sources:
- "Record-breaking bird migration revealed in new research" (https://www.ncl.ac.uk)
- "Overland movement and migration phenology in relation to breeding of Arctic Terns Sterna paradisaea" (https://onlinelibrary.wiley.com)
- "Tracking of Arctic terns Sterna paradisaea reveals longest animal migration" (https://www.pnas.org)
- "First evidence of the impact of climate change on Arctic Terns" (https://www.ncl.ac.uk)
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