Shorebirds sail Pacific Flyway

Estuaries provide critical winter havens

By Lynda V. Mapes | The Seattle Times • Published October 04, 2008

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PORT SUSAN BAY — All around Puget Sound, fall signals not the end, but the beginning of a new life cycle, as shorebirds just passing through, or arriving to spend the winter, touch down from the far north.

The great fall migration of birds along the Pacific Flyway from northern breeding grounds to southern overwintering areas is under way.

Port Susan Bay and neighboring Skagit Bay are home to the highest concentrations of shorebirds in Puget Sound. It's a hot spot for the fall shorebird migration and hosts the largest overwintering populations of shorebirds in Puget Sound, with more than 50,000 birds.

Panoply of species

Snow geese were a glittering white mirage at Port Susan Bay, as the first of thousands of the showy white birds began arriving from the high Arctic just this week to overwinter.

Dunlin sandpipers, also here to stay until spring, were drilling the mudflats with busy bills, and wigeon, those modest waterfowl, were piping soft conversation from the shallows.

Yellowlegs, some passing through on their way south, and some here to stay for the winter, mingled with dowitchers drowsing on one leg, their long bills tucked under their wings as they napped.

Resting up here is crucial to their survival as they make their journey south to California and South America.

The estuarine habitat of Port Susan, where the saltwater of Puget Sound reaches the delta of the Stillaguamish River, is among the most productive on Earth. The sheer biomass available for these birds to chow down is what draws them, and sustains them in their long-haul migrations.

Deltas dried, drained

Throughout Puget Sound country, the deltas of the region's great rivers all used to be home to thousands of shorebirds such as these. But as the deltas were diked and drained, and the shorelines developed, the amount of estuarine habitat has shrunk to just about 15 to 20 percent of what used to be available around Puget Sound.

"If they don't have this, they are in serious trouble," said Robert Warren, Port Susan Bay project manager for the conservancy. "It's important not just for shorebirds, but overwintering waterfowl and even salmon."