How does the Arctic tern's migration connect the Arctic and subantarctic regions?

The Arctic tern (Sterna paradisaea) connects the Arctic and subantarctic regions by performing the longest annual migration of any bird.12

This species breeds in the southerly reaches of the Arctic during the northern summer, taking advantage of the region's high productivity. As winter approaches and food resources in the north become scarce, the birds migrate to the Antarctic regions. This round-trip journey spans approximately 60,000 to 82,000 km (roughly 37,000 to 51,000 miles).123

By moving between these two polar extremes, the Arctic tern effectively exploits seasonal peaks in food production in both hemispheres, demonstrating a life cycle closely attuned to the productivity fluctuations of its respective habitats.3