Migratory Arctic Tern

Fascinating facts about the Migratory Arctic Tern

• Every year the Arctic tern flies pole to pole, a round trip of roughly 70,000 km. Over a 30-year life that's equal to flying to the Moon and back three times. They navigate by stars, a magnetic compass in their skull, and the polarisation pattern of sunlight. No animal sees more daylight in a year than they do.
• A study from 2010 tracked individual Arctic terns with geolocators and found they experience two summers every 12 months, fleeing Arctic winter for Antarctic summer, then back again. This means they chase eternal spring for their entire lives, spending roughly 8 months in active migration. They compress a year's worth of daylight into the hours they're actually awake.
• Arctic terns weigh less than 100 grams but their fuel efficiency is staggering: they burn roughly 0.75 grams of fat per day during migration, the metabolic equivalent of a human driving 1,600 kilometres on a single litre of petrol. They stop at staging posts, the same beaches, the same lagoons, year after year, refuelling before the next leg.
• Newly fledged Arctic tern chicks navigate their first migration without a parent or map. Genetic programming hardwired over millions of years tells them when to leave, which direction to fly, and where to stop. Some juvenile terns reach Antarctica having never been there before, guided only by inherited instruction, a living algorithm encoded in their brain.
• Climate change is rewriting Arctic tern survival. As sea ice melts earlier each spring, fish populations shift northward, but terns are still arriving on their ancient schedule. Misalignment of just two weeks between arrival and food availability can halve breeding success. A species that survived ice ages is now racing against the calendar it evolved to read.

At a glance

About the Migratory Arctic Tern

As the Arctic tern embarks on its odyssey, a mesmerizing spectacle unfolds, with the bird tracing an annual journey of over 40,000 miles, a testament to its unyielding endurance and innate navigational prowess. With wings beating in a blur of motion, it dances across the sky, its slender form etched against the horizon as it traverses the globe, driven by an ancient instinct to seek the perpetual daylight of the polar summers. In this remarkable pilgrimage, the Arctic tern weaves a tale of resilience and wonder, its path a soaring arc that bridges the hemispheres, a true marvel of the natural world.

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