The Facts

Bird Basics

Several million shorebirds pass over the Fraser River Estuary each year in migration and tens of thousands remain in the winter. The mudflats on Roberts Bank in the center of the estuary harbor the greatest number of shorebirds. Over 500,000 western sandpipers have been estimated to use the mudflat on a single day in spring migration. The mudflats are many kilometers wide during low tide. The mud teams with tiny invertebrates – in some places over 1000 invertebrates have been tallied in a 10 cm diameter core of mud. And on the surface, tiny diatoms and bacteria coat the mud in a greenish hue that western sandpiper dab from the surface with specialized tongues. In the marshes, dowitchers probe for marine worms and yellowlegs dart after small fish. On the sandflats, black-bellied plovers and dunlins pursue marine worms.

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​The Boundary Bay - Roberts Bank - Sturgeon Bank site (Fraser River Estuary) is a large complex of interconnected marine, estuarine, freshwater and agricultural habitats in southwestern British Columbia near the city of Vancouver. It includes Boundary Bay, a predominantly marine ecosystem, the estuarine waters of Sturgeon Bank, between the north and south arms of the Fraser River, and Roberts Bank, south of the south arm of the Fraser River. Maritime habitats in the IBA include sand and mud flats, eelgrass, salt marshes, estuarine marshes with sedge, cattails and bulrush and deeper tidal waters. Agricultural habitats within the IBA include the fertile, deltaic farmlands of Richmond, Delta, and south Surrey, which provide important habitat for waterfowl, shorebirds and birds of prey. Patches of forest, including mature coastal Douglas-fir, provide important nesting and roosting habitat for Great Blue Herons and raptors, including Bald Eagles. The network of rivers (Fraser, Serpentine, Nicomekl and Little Campbell) and associated wetlands within the site provided historical as well as current and potential future habitat for waterbirds. Burns Bog, lying in the heart of the delta, is a sphagnum moss wetland surrounded by shore pine and alder forest.