What our planet’s greatest travellers can tell us about Arctic connectivity

The Arctic tern breeds at the top of the world and winters at the bottom of it—a round trip of up to 70,000 kilometres every year. Its extraordinary journey, like so many Arctic animal migrations, perfectly embodies the far-reaching connections that tie the Arctic region to every corner of the planet. As COURTNEY PRICE and REAGAN AYLMER explain, understanding and protecting those connection pathways, both on land and sea, is at the heart of CAFF’s work on connectivity.

Stand on a rocky Arctic coastline under the midnight sun and you will hear the terns before you see them, a sharp cackling from birds that weigh barely 100 grams.

These tiny, social birds make fiercely protective parents, known to dive-bomb anything—from fox to eagle to human—that comes too close to their nests. They are noisy, resourceful and improbably small for what they are about to do: when the season ends and the polar light fades, these birds leave their breeding grounds across the circumpolar Arctic and chase the sun southwards via the Atlantic, past the coast of West Africa, and down into the Southern Ocean that surrounds Antarctica.

Then, after a few months of hunting and fishing under the Antarctic sun, they turn around and journey all the way back to the Arctic. A single tern will travel the equivalent of three round trips to the moon over its 30-year lifespan.

Erratic population changes

About 200 bird species breed in the Arctic each summer, and almost all are migratory. Their routes span every continent and ocean, connecting the Arctic biologically, ecologically and even socially to the rest of the planet. As the Arctic Migratory Birds Initiative Flyways show, these birds are forever on the move, travelling down migratory corridors (called flyways) and connecting us all.

But their journeys are becoming more challenging. International monitoring data tell a story of stark and uneven population declines. CAFF’s Arctic Species Trend Index, which tracks population trends across more than 300 Arctic species, and the 2021 State of the Arctic Terrestrial Biodiversity Report, which assessed 88 tundra-breeding bird species, reveal the same troubling picture: some populations are stable or recovering while others are in freefall. in freefall.

For shorebirds—the sandpipers and knots whose calls define an Arctic summer—the losses have been severe. More than half of all these wader species are declining, with populations along the East Asian-Australasian Flyway down by as much as 70 per cent. Some species have lost up to 90 per cent of their numbers over the last few decades.

But the Arctic is only part of the story. The rest and refuelling stopovers that birds depend on mid-migration, like intertidal mudflats and coastal estuaries, are disappearing as development increases. Illegal hunting takes a further toll that is, by its nature, difficult to account for. Climate change is scrambling the seasonal cues that birds and their prey have relied upon for millennia: snowmelt and shifting time frames for insect emergence make it harder for parents to feed and raise their chicks.

For example, a strong breeding season in the Russian tundra counts for little if the stopover a bird depends on weeks later has been paved over. In other words, what happens at one end of a migration route is inseparable from what happens at the other. Any conservation approach must be built around these connections.

Applying the same ideas to marine life

The same principle holds true beneath the waves. CAFF’s State of the Arctic Marine Biodiversity Report showcases how beluga whales, bowhead whales and ringed seals undertake migration routes that span multiple national jurisdictions. Protecting them requires exactly the kind of cross-border coordination that AMBI has pioneered for birds.

In Hudson Bay, belugas are already showing us what happens when the ecological script starts to shift: their migration timing has moved in response to warming waters. Sea ice retreat doesn’t only mean less ice.

Its disappearance also unravels a delicate system that places food sources in the right place at the right time, builds routes that have been consistent across centuries, and affects Arctic wildlife whose survival depends on the existence of these unique connections.

CAFF and Protection of the Arctic Marine Environment (PAME) are now developing a marine spatial planning tool that will identify and prioritize the areas that sea ice-dependent species rely on most and put that knowledge directly into the hands of those who decide what gets protected. Understanding where the connections are strongest is the first step to keeping them intact.

As summer draws to a close, an Arctic tern flies from its nest on a rocky shoreline and turns south, beginning a journey that will take it through the jurisdictions of dozens of nations, across habitats that are variously protected and unprotected, monitored and overlooked.

Migration is the Arctic’s oldest and most insistent argument for global cooperation. In that context, CAFF’s work to understand and advance connectivity remains essential.