The arctic tern (Sterna paradisaea) makes the longest known migration of any animal on Earth — an annual round-trip of up to 70,000 miles (112,000 km) between its Arctic breeding grounds and Antarctic wintering areas. A single arctic tern may travel the equivalent of three trips to the Moon and back in its lifetime — which can exceed 30 years.
The Ultimate Migrant
Arctic terns breed on Alaska’s tundra, beaches, and rocky shores in summer, then fly south along oceanic routes to spend the Antarctic summer in the Southern Ocean. They chase summer perpetually — experiencing more daylight than any other animal on Earth.
Their migration route is not a straight line. Recent tracking studies have revealed that arctic terns follow the prevailing winds across the Atlantic and Indian Oceans in a complex S-shaped path — minimizing energy expenditure on the world’s longest commute.
Aerial Masters
Arctic terns are among the most elegant fliers in nature. They hover above the water on rapidly beating wings, then plunge headfirst to catch small fish near the surface. Their deeply forked tail and long, narrow wings give them extraordinary maneuverability.
Despite their small size — typically weighing only 3–4 oz — arctic terns are famously aggressive defenders of their nesting colonies. They will dive-bomb and strike any intruder, including humans, bears, and Arctic foxes.
Climate Threat
Arctic terns face increasing pressure from rapid Arctic change:
- Breeding habitat loss from permafrost thaw and coastal erosion
- Prey shifts as ocean warming changes fish and krill distribution
- Disrupted migration cues from altered atmospheric patterns
The Alaska SeaLife Center’s seabird monitoring program tracks tern populations in the Gulf of Alaska, contributing to long-term datasets critical for understanding climate impacts on Alaska seabirds.