Alaska's Shorebirds: USGS Research on Long-Distance Migrants

By Dan Ruthrauff, Lee Tibbitts and John Pearce. USGS Fact Sheet 2020–3056, November 2020.

Dunlins wheel through the air before fall migration, Egegik, Alaska. USGS photo.

Shorebirds in decline

Shorebirds — sandpipers, plovers, oystercatchers and their kin — are best known for running along the water's edge, probing for food. Less known are their epic migrations: millions fly in from around the globe to breed in Alaska each spring, making them part of local wildlife and of Alaska Native cultures.

Many shorebird populations have declined steeply worldwide. They use the same coasts people do, and development shrinks and degrades their habitat. Alaska, by contrast, still has abundant intact coastal ecosystems for breeding and migratory stopovers, which makes it one of the world's most critical places for shorebirds. The USGS Alaska Science Center works to find the sites that matter most and to learn why so many populations are falling.

Global citizens

Nearly all of Alaska's breeding shorebirds spend the rest of the year in North, Central or South America, Asia, Oceania, Australia or New Zealand. They depend on chains of healthy sites, often thousands of miles apart, that supply food and safety along the way. The Center works with international partners to see how events anywhere in the annual cycle affect them.

A male bar-tailed godwit flying along the Bering Sea coast near Kotzebue, Alaska. U.S. Fish and Wildlife Service photo.

Bar-tailed godwits:

• Record flight: their fall migration is a single nonstop crossing of the central Pacific, 7,000 miles in 9 days — the world's longest nonstop bird migration.
• Population: about 125,000 birds, breeding in coastal wetlands of western and northern Alaska and fueling up at estuaries in western Alaska.
• Winter: in New Zealand and eastern Australia, where adult survival and numbers have recently declined.
• The bottleneck: each spring they spend about 1 month refueling in the Yellow Sea, where coastal wetlands have suffered unprecedented loss.

Pinning down threats is hard: harm in one season may not show until another. So the Center studies many species at many sites, building a fuller picture of what shorebirds face.

A changing climate

Warming hits high latitudes hardest. Habitat change, drying wetlands and rising seas threaten Alaska's breeding shorebirds, and migrants face climate shifts elsewhere too. Species that can adjust may fare better.

A marbled godwit on its breeding grounds near Ugashik, Alaska. USGS photo.

• Marbled godwits: Alaska's population returns to the same coastal sites in the Pacific Northwest every year, but changes how long it stays and when, with the conditions — a flexibility no one had appreciated.
• Bristle-thighed curlews: studied by the Center since 2012, they breed only in Alaska and winter on low atolls and islands across Oceania, highly exposed to sea-level rise. Their recent colonization of an upland site on Oahu, Hawaii — where managers controlled predators and improved foraging — shows how habitat management can help.

A bristle-thighed curlew outside Nome, Alaska. USGS photo.

• Rock sandpipers: they winter farther north than any other Pacific shorebird, on the icy shores of Cook Inlet. They survive by raising their metabolic rate as much as sevenfold, eating hundreds of energy-rich clams a day — a demand expected to ease as Alaska's winters grow milder. For them, some warming may even help.

A rock sandpiper eating a small clam (Macoma balthica) on frozen mudflats near Kasilof, Alaska. USGS photo.

Understanding how shorebirds fit into their environments, and their importance to Alaska Native culture, is key to planning for their future. The Center's research and outreach bring human, seasonal and geographic perspectives together.

Sources

Based on Shorebird Research at the U.S. Geological Survey Alaska Science Center, by Dan Ruthrauff, Lee Tibbitts and John Pearce, USGS Fact Sheet 2020–3056, U.S. Geological Survey; a work of the United States government in the public domain. The USGS and USFWS photographs are taken from the fact sheet's PDF; three photographs courtesy of Zak Pohlen, used with permission, are not reproduced.