Arctic Tern Travels From Pole to Pole
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The medium-sized sea bird called the Arctic tern is famous not only for its slender, elegant appearance – their body is white and grey, their beaks and legs are bright red and they wear a black nape – but also for their extraordinary migration patterns: Arctic tern travels round trip from the Arctic to the Antarctic, which makes it possible for them to enjoy two summers a year.
Terns breed in the Arctic, then they set on their long journey to the Antarctic, then return to their breeding grounds. The straight line distance between the Arctic and the Antarctic is about 19,000 km, but terns do not fly straight, the distance they cover being more likely to be somewhere around 22,000 km there and the same distance back. Some terns are known to have covered a stunning 71,000 km, while others even 90,000 km during the course of one single year!
Arctic terns reach sexual maturity at around the age of three or four. They are known to mate for life and they usually stay with the same colony all their life, too. Breeding happens on coasts, on islands, sometimes on tundra, but always close to the water. The male and the female choose the place for the nest together and they both defend the territory. They are known to be fierce when they protect their eggs or their young. The female usually lays two eggs and the male and the female take turns sitting on the eggs. The eggs hatch after about three or four weeks.
Arctic terns mainly feed on crustaceans such as amphipods and krill, as well as on small fish, especially capelin, cod, and herring. The young are taught by their parents how to catch food very soon after they are fledged – juvenile terns become able to fly after about three weeks following hatching, and that is when they learn how to feed on their own as well, including the complex and difficult method of plunge-diving.
During their migration, Arctic terns have their own favorite places. They do not spend the same amount of time at resting spots, one of their preferred spots being on the western part of the North Atlantic Ridge, where they spend more than 3 weeks;
They usually cover about 520 km a day, but some of them are known to have covered almost 700 km per day;
The study of Arctic terns and their migration routes has helped scientists discover ocean hotspots – areas of increased volcanic activity – that were previously unknown to them.
Finally, the fact that the Arctic tern travels round trip from the Arctic to the Antarctic may be impressive, but here’s one last bit that will leave you in awe: the total distance this bird covers during its lifetime is more than 2.4 million km (around 1.5 million miles) – the equivalent of 3 trips to the Moon and back!
The Epic Journey of the Arctic Tern: From Pole to Pole
Embarking on one of the most remarkable migratory journeys in the animal kingdom, the Arctic Tern (Sterna paradisaea) is a true marvel of nature. These small, yet formidable birds undertake an annual migration that spans from the Arctic to the Antarctic and back, covering an astonishing distance of about 71,000 kilometers (44,000 miles). This incredible journey not only showcases the Arctic Tern’s remarkable endurance but also its intricate navigation skills, allowing it to traverse vast oceans and continents. In this exploration, we delve into the intricacies of their migration, the challenges they face, and the unique adaptations that enable them to survive and thrive in some of the most extreme environments on Earth.
Unraveling the Mysteries of Migration
The Path Less Traveled
The Arctic Tern’s migration is not just about the impressive distance; it’s the path they take that’s truly fascinating. Opting for a convoluted route that maximizes wind assistance, these birds demonstrate an unparalleled understanding of atmospheric dynamics. Their journey involves a series of zigzags and detours, exploiting prevailing wind systems to conserve energy, a tactic that exemplifies their strategic prowess in navigation.
Navigational Marvels
How do these birds, with brains no bigger than a walnut, navigate across hemispheres with such precision? The Arctic Terns are equipped with a sophisticated internal compass, guided by the Earth’s magnetic fields, and an innate ability to read the stars. This celestial navigation, coupled with their acute sensitivity to the Earth’s magnetic anomalies, allows them to chart a course that’s both efficient and effective, showcasing nature’s ingenuity at its finest.
Adaptations for Endurance
Built for the Long Haul
The Arctic Tern’s physical adaptations are key to its migratory success. Their slender wings and streamlined bodies are designed for maximum aerodynamic efficiency, allowing them to glide effortlessly over vast distances. Moreover, their ability to sleep while flying, by shutting down one hemisphere of their brain at a time, ensures they remain vigilant against predators while conserving energy.
Dietary Strategies
Sustaining such a long journey requires a strategic approach to nutrition. Arctic Terns are opportunistic feeders, their diet mainly consisting of fish and small marine invertebrates. They employ a technique called “dip-feeding,” skimming the ocean’s surface without fully landing, which enables them to eat on the go. This ability to forage in diverse marine environments ensures they have a constant energy supply throughout their migration.
Challenges Along the Way
Predators and Perils
The Arctic Tern’s journey is fraught with dangers, from natural predators like skuas and falcons to human-induced threats such as habitat loss and climate change. Their breeding grounds in the Arctic are particularly vulnerable, with the encroaching effects of global warming disrupting their nesting sites and food availability, posing significant challenges to their survival.
The Toll of Climate Change
Climate change is not just altering their breeding grounds but also affecting their migratory routes. Changes in sea temperatures and currents are impacting the abundance and distribution of their prey, forcing the Arctic Terns to alter their age-old migratory paths. This adaptability is a testament to their resilience but also highlights the precarious balance of their existence in the face of rapid environmental changes.
In conclusion, the Arctic Tern’s journey from pole to pole is not just a testament to their incredible endurance and navigational skills but also a reflection of the intricate balance of ecosystems. Their migration offers valuable insights into the impacts of climate change, underscoring the urgency for conservation efforts to ensure the survival of this and other migratory species.
FAQs About Arctic Tern Migration
- How long does the Arctic Tern’s migration take? The Arctic Tern’s migration can take up to several months, depending on weather conditions, wind patterns, and the specific routes taken. They typically begin their southward journey in August or September and return to their Arctic breeding grounds around May.
- Why do Arctic Terns migrate such long distances? Arctic Terns migrate to exploit the long Arctic summer days for breeding, taking advantage of the abundant food resources. In the winter, they head to Antarctic waters to enjoy the austral summer, thus avoiding harsh winter conditions and maintaining access to plentiful food supplies.
- How do Arctic Terns know where to go during their migration? Arctic Terns rely on a combination of genetic predisposition, celestial navigation, and the Earth’s magnetic fields to guide their migration. Their innate ability to navigate using the stars and magnetic cues helps them find their way across vast distances with remarkable accuracy.
- What do Arctic Terns eat during their migration? During their migration, Arctic Terns primarily feed on small fish and marine invertebrates. They are skilled hunters, often catching prey just below the water’s surface while in flight, allowing them to sustain themselves over the long journey.
- How are Arctic Terns affected by climate change? Climate change impacts Arctic Terns in multiple ways, including altering their breeding grounds due to melting ice and changing the distribution and abundance of their prey along migratory routes. These changes force them to adapt their migration patterns and may threaten their long-term survival.