The Arctic Tern: Master of Long-Distance Migration

The Arctic tern (Sterna paradisaea) is a member of the tern family, Sternidae, and is often simply referred to as a tern. This elegant and lightweight seabird weighs only around 100 grams (3.5 ounces), yet it is famous for its incredible endurance and extraordinary migrations.

Adult Arctic terns can be identified by their deeply forked tails, black head caps, and dark red bills and legs. Their bodies are mostly white, with light gray backs and black tips on their wings. Young terns look different from adults, having darker bills and feet and lacking the distinctive long tail feathers.

The Arctic tern is strongly associated with the northern summer and is one of the most recognizable birds of Arctic regions. It breeds throughout the circumpolar zone, including areas around Svalbard and Greenland, while also nesting in parts of Europe as far south as Britain and the Netherlands.

In Iceland, Arctic terns can be found throughout the country, though they usually choose nesting sites near the coastline. Some smaller colonies also exist in highland areas near large lakes. The birds typically arrive in Iceland during April or May, and many Icelanders consider their return a sign that spring has arrived, much like the arrival of the beloved golden plover.

Discover Iceland’s Wildlife and Nature in One Location

Perlan in Reykjavik is one of Iceland’s most famous nature centers, providing visitors with an opportunity to explore and learn about the country’s unique environment.

Guests can experience a realistic ice cave, interactive displays, a detailed recreation of a bird cliff, and a volcanic exhibition. The planetarium dome offers a virtual northern lights experience, while the Icelandic Museum of Natural History presents engaging exhibits that explore the importance of water in Iceland’s natural world.

Through these exhibitions, visitors can gain a deeper understanding of Iceland’s landscapes, wildlife, and natural forces.

Arctic Tern Population and Nesting Behavior in Iceland

Iceland supports a large Arctic tern population, although numbers have declined in recent years. The country is estimated to contain around 150,000 to 250,000 breeding pairs, making it one of the most important breeding regions for European Arctic terns.

Large colonies can be found in many areas of Iceland, including locations such as Rif, Jökulsárlón, Vík, and Hrísey, which is believed to be home to one of the largest Arctic tern colonies in Europe.

The nesting habits of Arctic terns are relatively simple. Instead of building complex nests, they usually create a small depression in the ground where they lay two to three small eggs. These eggs are typically brown in color with dark markings.

Egg laying generally begins in June, and incubation lasts around 20 to 22 days. After hatching, adult birds continue feeding their chicks for approximately three to four weeks until the young birds are strong enough to fly.

The diet of young Arctic terns mainly consists of small fish. Coastal chicks often feed on sand eels, while inland chicks may eat sticklebacks found in lakes and rivers. When fish supplies are limited, the birds also consume insects and other small invertebrates.

Changes in Iceland’s sand eel population in recent years have negatively affected chick survival, as these fish are an important food source for growing young birds.

The Incredible Journey Between the Arctic and Antarctic

Arctic terns spend much of their lives in flight, traveling between the northern and southern polar regions. They only spend short periods resting or staying in one place while nesting and raising chicks.

These birds are exceptionally skilled fliers. They can hover in the air while searching for food before suddenly diving downward to catch prey. Their impressive flying abilities also make them highly effective at defending their nesting areas.

Anyone who enters an Arctic tern colony quickly discovers how protective these birds can be. Entire groups may rise into the air, making repeated dives toward intruders and sometimes striking at their heads with their sharp beaks. Their aggressive defense behavior provides protection not only for themselves but also for other birds that choose to nest nearby.

When summer ends in the Northern Hemisphere, Arctic terns begin one of the longest migrations in the animal world. They follow seasonal changes and travel southward toward regions such as South Africa and Antarctica.

Many Arctic terns spend the winter months near Antarctica, meaning they experience two summers every year and receive more daylight throughout their lives than almost any other animal on Earth.

Five Amazing Facts About the Arctic Tern

The Arctic tern’s lifetime journey is truly extraordinary. Scientists estimate that an individual bird may travel a distance equivalent to flying to the moon and back approximately three times during its lifetime.

Arctic terns are capable of reaching speeds of about 60 kilometers per hour (37 miles per hour) during flight. They can complete the journey between the Arctic and Antarctic regions in only around 90 days.

Their migration is considered one of nature’s greatest achievements. No other bird species regularly completes such extreme journeys, with Arctic terns traveling an average of about 44,100 miles every year.

While flying, Arctic terns can remain suspended in the air as they search for fish or watch for threats before making a rapid dive. This ability to hover and maneuver precisely is one of the most impressive flight skills displayed by birds in Iceland.

Despite their remarkable flying abilities, Arctic terns still face dangers from predators. Arctic skuas are highly skilled fliers and are known to chase Arctic terns in order to steal the fish they have caught. These aerial battles demonstrate the challenges these small but powerful birds face throughout their lives.