72 Microseasons of the Pacific Northwest

Every spring, one of North America's most spectacular wildlife events unfolds on the mudflats and estuaries of the Pacific Northwest coast: the northbound shorebird migration. Hundreds of thousands of western sandpipers (Calidris mauri), dunlin (C. alpina), black-bellied plovers (Pluvialis squatarola), short-billed dowitchers, whimbrel, and more than a dozen other species descend on coastal stopover sites to fuel their journeys to Arctic breeding grounds. The timing peaks between late April and mid-May, and the spectacle is accessible to any visitor willing to time a visit to the outgoing tide. Grays Harbor National Wildlife Refuge near Hoquiam, Washington, is the single most important stopover site on the Pacific Flyway between California and Alaska. On peak days in late April and early May, the mudflats and shallow water hold 500,000 or more shorebirds — the largest concentration of shorebirds on the Pacific Coast of North America. The Bowerman Basin unit of the refuge offers viewing from a short trail. As the tide rises and pushes birds off the flats, they lift in enormous swirling flocks — a "shorebird cloud" that twists and flashes as birds bank together, revealing white undersides then dark upperparts in mesmerizing synchrony. On the Oregon coast, Tillamook Bay, Netarts Bay, Yaquina Bay near Newport, and Bandon Marsh National Wildlife Refuge all host significant concentrations. On southern Vancouver Island, the Boundary Bay flats attract both migrant shorebirds and the birders who travel from across North America to watch them. Even Puget Sound observers will find the inner bay at Nisqually National Wildlife Refuge and the tidal flats near Ediz Hook in Port Angeles productive during peak migration.