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10 Fascinating Facts about Arctic Terns You Never Knew!

The Arctic Tern or Sterna paradisaea is a graceful and elegant bird that thrives in the Arctic region. This species is interestingly named the ‘Tern’ after the word ‘turn’ due to their exceptional ability to change their flight path quickly and seamlessly.

They are easily identifiable by their distinct black cap, white neck, silver-grey wings, and a deeply forked tail. Here, we will explore the identification of Arctic Terns, including their field identification and similar species, as well as their detailed plumage and molts.

Field Identification

The Arctic Tern is easily distinguishable from other species by its unique characteristics. They are medium-sized birds that grow up to 38cm in length, with a wingspan of 76cm.

They can be identified by their silvery-grey wings, white underside and tail which is deeply and elegantly forked. The black cap extends beyond the eye, down the nape, and towards the neck.

The beak is dark crimson, and the red legs help to differentiate them from other terns. Arctic Tern juveniles have grey-brown feathers on their back, with a black bill and legs.

The young Arctic Terns take three years to mature, during which their plumage changes before they attain their distinctive silver-grey and white colors.

Similar Species

Arctic Terns can be confused with other Terns and Gulls. The Common Tern is the likeliest to be mistaken for the Arctic Tern.

However, they are smaller, and their tails are less deep and forked, with a pale grey back in contrast to the Arctic Tern’s typical darker back. The Forster’s Tern is also an identical species because it has a white face and underbody, but the wings are paler than the Arctic Tern wings.

In addition, Forster’s Terns have black caps and, unlike the Arctic Tern, very small red bills.



Arctic Terns undertake a significant molt every year, replacing their feathers in a process known as molting. They molt their primary and secondary feathers alternately, with the primary feathers replaced entirely within a year and the secondary feathers replaced during the following year.

Molting can present a difficult time for Terns as they become flightless during the process. Fortunately, they have an alternative feeding ground to shift to during this period along with their long migrations.

In conclusion, the Arctic Tern, known for its remarkable flight abilities, identification, and unique plumage, is a remarkable bird species in the Arctic region. Understanding their physical characteristics, distinctive field identification, and molting process are essential aspects for birdwatchers, researchers, and conservationists alike.

So, the next time you’re out exploring the Arctic, why not keep your eyes out for the beautiful and fascinating Arctic Tern? The study of systematic history is crucial in understanding the evolutionary relationships between different species and how they evolved over time.

In this article, we will dive into the systematic history of the Arctic Tern, exploring its geographic variation, subspecies, related species, and historical changes to distribution.

Geographic Variation

The Arctic Tern is widely distributed throughout the Arctic region, and different populations of these seabirds exhibit variations in plumage, size, and vocalizations. The birds breeding in Eurasia are generally smaller and paler than those breeding in North America.

Furthermore, Arctic Terns breeding at the edges of the Arctic have longer bills than Terns breeding further into the Arctic. These variations suggest that the Arctic Tern is not a uniform species, but rather a set of populations with varying characteristics shaped by local environmental conditions.


The Arctic Tern has several recognized subspecies that differ slightly in their physical characteristics and breeding habitats:

1. Sterna paradisaea paradisaea – This subspecies breeds throughout the Arctic regions of Eurasia and migrates to the Antarctic region during the non-breeding season.

2. Sterna paradisaea aleutica – This subspecies breeds along the Aleutian Islands and Alaska coast and winters in the central to the western Pacific Ocean.

3. Sterna paradisaea longipennis – This subspecies breeds along the eastern seaboard of North America, from northern Canada to Maine, and winters in the southern Atlantic and Pacific Oceans.

4. Sterna paradisaea tethys – This subspecies breeds on the islands in the North Atlantic and winters in the South Atlantic.

Related Species

The Arctic Tern belongs to the family of seabirds known as Laridae, which also includes Gulls, Skimmers, and Terns. The Arctic Tern is most closely related to other members of the genus Sterna, including the Common Tern (Sterna hirundo), the Roseate Tern (Sterna dougallii), and the Little Tern (Sternula albifrons).

These Terns share many physical characteristics, including long wings, pointy bills, and webbed feet that make them skilled fliers and divers.

Historical Changes to Distribution

The distribution of Arctic Terns has changed significantly over time due to climate change, human activities, and other environmental factors. During the last glacial maximum, about 20,000 years ago, the Arctic Terns’ breeding grounds were covered by ice, and populations were confined to the temperate regions of North America and Eurasia.

As the ice receded, Terns gradually spread to the newly exposed land, resulting in increased breeding populations across the Arctic. In recent years, the Arctic Tern has faced several threats that have affected their distribution.

Climate change has led to drastic changes in the Arctic ecosystem, such as melting sea ice and disappearing prey species. These factors have forced Arctic Terns to adapt to new environments, resulting in changes to their migratory patterns and breeding habitats.

In addition, human activities, including oil and gas exploration and hunting, have also disrupted Arctic Tern populations, leading to reduced numbers in some regions. In conclusion, understanding the systematic history of the Arctic Tern is essential in comprehending the evolutionary relationships between different species and how they adapt to changing environmental conditions.

While the Arctic Tern continues to face threats to its distribution and population numbers, conservation efforts and continued research on these fascinating birds can help mitigate these challenges and ensure their survival for years to come. The Arctic Tern, or Sterna paradisaea, is a bird species that thrives in sub-Arctic and Arctic regions.

These seabirds are renowned for their fascinating movements and long-distance migrations and can be found breeding on rocky islands and coasts. In this article, we will examine the habitat, movements and migration of the Arctic Tern.


Arctic Terns breed over an extensive range around the Arctic, from Greenland and Canada to Russia and Scandinavia. They primarily breed on coastal or offshore islands, relying on colder sea temperatures to keep the plankton population abundant, ensuring a reliable food source for the chicks.

During the breeding season, they build nests near shallow waters across rocky cliffs or beaches. The nests contain two to three eggs, with both parents taking responsibility for their incubation and chick feeding.

In the winter, Arctic Terns abandon the cold Arctic regions in search of warmer areas such as the Southern Ocean, Antarctica, and the Pacific coasts of both North and South America. These winter destinations offer ample marine food sources necessary for their survival.

Movements and Migration

Arctic Terns have one of the most remarkable migratory patterns of any bird species, as they travel extraordinary distances every year. Some Arctic Terns migrate as much as 44,100 miles per year, which is equivalent to flying around the Earth twice! During their migration, they travel north and south between Antarctica and the Arctic, depending on the season.

This journey is important to the survival of this species, as they follow the abundance of fish and plankton, which makes up a large part of their diet. The Arctic Tern experiences the longest migration of any bird in the world, with each annual cycle lasting up to 6 months! During migration, Arctic Terns do not fly in a straight line, but rather follow meandering routes to exploit prevailing winds.

They sometimes stop at pit stops for feeding and rest, enabling them to maintain their stamina for their long journeys. Due to their prowess in flight, high endurance, and incredible navigational skills, Arctic Terns can exploit air currents, fly at high altitudes and manage to alter their direction and speed as the climate changes.

Interestingly, Arctic Terns have an uncanny ability to find their way back to their breeding colonies even after travelling thousands of miles away for several months. They use a combination of instinct, visual orientation, and the Earth’s magnetic field to navigate across the vast oceans and reach their breeding colonies.

Studies have also shown that they use odours associated with their breeding habitats to find their way back to their colonies. In conclusion, the Arctic Tern is a remarkable bird species that thrives in sub-Arctic and Arctic regions.

They breed along rocky coasts and islands and undertake an incredible long-distance migration every year to the southernmost tip of the planet. Understanding the movements and habitat of Arctic Terns is crucial for conservation efforts and the preservation of this fascinating bird species for future generations.

Arctic Terns are fascinating seabirds known for their incredible journeys and remarkable adaptations to life in the harsh Arctic environment. In this article, we will explore two critical aspects of the Arctic Tern’s life: its diet and foraging habits and its sounds and vocal behavior.

Diet and Foraging

Arctic Terns are highly adapted to life at sea and rely on small fish and invertebrates as their primary food source. They are known to forage for small fish, such as sand eels and herring, diving to depths of up to 2 meters and catching prey in their sharp, pointed bills.

These birds can also feed on marine invertebrates, such as shrimp and squid, that form dense populations in the ocean waters that they inhabit.


During feeding, Arctic Terns can be seen flying a few feet above the surface of the water, scanning for prey. When prey is spotted, they will tilt their wings and make a sudden dive, plunging into the water in pursuit of their prey.

Once they have located a shoal of fish or squid, they can dip down repeatedly and pick off prey with great precision and agility.


The Arctic Tern’s diet varies depending on the seasons and locations, based on the abundance of the prey items. During the breeding season, they tend to focus on small fish, such as sand eels, which are more abundant in the Arctic waters.

In contrast, during the winter seasons, Arctic Terns feed on krill, shrimp, squid, and similar invertebrates found in the warmer waters around Antarctica.

Metabolism and Temperature Regulation

Arctic Terns are uniquely adapted to life in the harsh, cold, and windy environment of the Arctic regions, which requires them to regulate their metabolism and body temperature actively. These birds maintain their body temperature by increasing their metabolism, allowing them to generate heat.

They also have a layer of insulating feathers that helps them conserve heat and maintain their body temperature even in freezing temperatures. During the breeding season, Arctic Terns are exposed to the cold, harsh elements of the Arctic environment, and therefore have to adjust their metabolic rate to counteract any loss of heat.

During the winter season, their metabolism lowers to conserve energy for survival without hindering their long migrations.

Sounds and Vocal Behavior

Arctic Terns engage in vocal behavior through a series of distinct vocalizations that have specific meanings and purposes. These birds employ several different sounds, ranging from simple chirps and whistles to more complex trills and calls.

These vocalizations have different purposes, including mate attraction, territory defense, and communication between nesting partners.


The most common sounds made by Arctic Terns include a series of whistles and trills that they use during courtship and mating. These sounds usually consist of a series of long, drawn-out notes that are repeated in quick succession.

They also produce a series of warning calls to warn their chicks of possible threats and predators. Arctic Terns are known for their adaptability, intelligence, remarkable foraging skills, and vocal behavior.

Given their unique adaptations to life in the Arctic and the conditions that they face during migrations, it’s critical to study their foraging behavior, metabolism, and vocalizations, as they play important roles in shaping and maintaining their populations. The Arctic Tern remains a significant bird species in the Arctic region, and their preservation and conservation require an understanding of their adaptations to survive in their unique habitats.

Arctic Terns are fascinating bird species that are well-known for their remarkable behavior, including locomotion, self-maintenance, sexual, and agonistic behavior. In this article, we will also examine Arctic Tern’s breeding habits, demography, and population.



Arctic Terns have a distinctive and graceful flight, and they have adapted well to long-distance, extremely challenging migrations. They are known to travel thousands of miles to and from their breeding and feeding habitats, and they can fly for incredibly long periods without resting.


Arctic Terns maintain their feathers by preening themselves to remove dirt and other unwanted elements. They also use oil produced by a gland near their tail base to keep their feathers waterproof.

These seabirds also take care of their feet, as they use their bills to remove any dirt and protect their sharp claws.

Agonistic Behavior

Arctic Terns are territorial birds, and they use aggressive, agonistic displays to protect their nesting sites and young from potential predators or other competing birds. These displays include calls, wing flapping, and diving, which serve as a warning to potential intruders.

Sexual Behavior

During the breeding season, male Arctic Terns use display flights to attract females. These display flights involve elaborate flying, calling, and diving behaviors.

Once pair bonding is established, male and female Arctic Terns will partner together and work to build a nest and incubate their eggs.


Arctic Terns engage in monogamous mating, forming long-term pair bonds with their partners. These seabirds breed on rocky islands in the Arctic Tundra, where they build shallow nests made of grass, seaweed, and other materials near the shoreline.

After mating, Arctic Terns lay their eggs, usually two to three per clutch, which they incubate for around twenty-one days. Parent Terns take turns incubating their eggs, with the male usually taking over during the daytime, while the female takes the night shift.

Once the chicks hatch, both parents take care of them, feeding them a regurgitated mixture of fish, squid, and crustaceans for up to sixty days. After this period, the chicks will learn how to fly, leave the breeding site, and start their journey to their non-breeding grounds.

Demography and Populations

Arctic Tern populations have been relatively stable over the past few decades, with around 1 million birds estimated globally. Despite this, Arctic Terns face threats from climate change, overfishing, and human activities.

These factors have led to changes in feeding and breeding habits, increased competition for resources, and the destruction of breeding habitats. Conservation efforts are keeping a close watch on Arctic Tern populations, particularly in areas where they are vulnerable.

It is essential to continue monitoring populations and engage in conservation efforts that preserve breeding habitats, protect migrating routes, and manage fishing and human activities that may threaten the survival of this species. In conclusion, the Arctic Tern is a remarkable bird species that has adapted well to life in the harsh and challenging environment of the Arctic.

Their unique behavior, mating habits, demography, and population dynamics make them vital to the Arctic ecosystem, and their conservation should be a top priority to ensure that these amazing birds survive for future generations. Arctic Terns are fascinating seabirds that thrive in the harsh and challenging environments of the Arctic region.

This article has highlighted their significant characteristics, including their remarkable behaviors, unique adaptations to the environment, and long-distance migrations that span the length of the planet. Moreover, it has focused on their diet and feeding habits, sexual and agonistic behaviors, and their breeding and demography, pointing towards their importance in the Arctic ecosystem.

Understanding the Arctic Tern’s way of life and unique adaptations is critical for their conservation and survival, ensuring that these remarkable birds continue to thrive in the years to come. Therefore, it is essential to continue monitoring their population numbers and engage in conservation efforts that preserve their breeding habitats, protect their migratory routes, and manage human activities that threaten their survival.

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