Importance to Waterbirds
Waterfowl utilize Washington’s coastal bays primarily during migration. American wigeon compose some 80% of these migrants, which may reach 50,000 birds per fall. Some 90,000 scoters are counted annually during midwinter surveys with over half occurring in western Washington (Ball et al. 1989). Large numbers of pintails migrate through these habitats. Canada geese are most numerous along Willapa Bay with a resident population of about 1,000 birds. Willapa Bay also holds between 800-1,500 Pacific brant in winter, with larger numbers staging in spring.
Lower Columbia River
The Lower Columbia River area includes both the Oregon and Washington shores of the river from Bonneville Dam to the mouth. The Columbia River Estuary encompasses over 40,000 ha. Although there are no dams on the Columbia River below Bonneville, the system has been dramatically altered through dredging, ditching, and construction of flood control levees. In addition, an extensive dam system on the lower tributaries to the Columbia River have dramatically altered natural hydrology, affecting the natural processes that form and maintain wetland habitats. The heavily developed Portland-Vancouver Metropolitan Area has degraded the river system by extensive levee construction and drainage of floodplain wetlands. Much of the flat alluvial plains of the Columbia are currently managed as pastures, with some areas planted to annual and perennial crops. Recently, the conversion of many of these areas to cottonwood tree farms has degraded prime waterfowl foraging areas. The extensive loss and conversion of floodplain habitats in the lower Columbia River has not only affected waterfowl habitat, but is one of the leading factors in the decline of other species, including 12 stocks of salmonids listed under the Endangered Species Act.
Important wetlands managed by public entities in the region include: Ridgefield, Steigerwald, Pierce and Julia Butler Hanson National Wildlife Refuges managed by the U.S. Fish and Wildlife Service; Shillapoo, Vancouver and Chinook River Wildlife Areas managed by the Washington Department of Fish and Wildlife; Oregon’s Sauvie Island and Burlington Bottoms Wildlife Areas; Smith and Bybee Lakes, and Multnomah Channel habitats managed by Metro (the regional government entity for the metropolitan area of Portland); and the Sandy River Delta and other Columbia River gorge habitats managed by the U.S. Forest Service. The Columbia Land Trust, a local non-profit conservation organization, has developed a significant land protection program and has secured extensive wetland habitats in the lower Columbia River, especially in the Grays River estuary near the mouth of the Columbia River.
Importance to Waterbirds
Over 150,000 ducks and geese use Sauvie Island and nearby wetland areas during peak migration. Over 250 avian species have been recorded there. Mallard, northern shoveler, American wigeon, northern pintail, and green-winged teal are the principle dabbling ducks, whereas, canvasback, ring-necked duck, and scaup are the principle diving ducks. Scaup and ring-necked ducks occur primarily in the Columbia River estuary. Aleutian and cackling Canada geese are migrants that pass through this region, and some 76,000 Canada geese winter in the Lower Columbia and Willamette Valley (Jarvis and Cornely 1988). Significant numbers of dusky Canada geese winter in this region. The Lower Columbia also supports the majority of the 8,000 tundra swans wintering in the Pacific Northwest (Ball et al. 1989). Wetland restoration projects in the region have also resulted in significant increases in numbers of locally breeding waterfowl, an important component of the local waterfowl harvest, particularly early in the season.
The Oregon Coast is characterized by a rugged coastline that is dissected by large rivers originating from the Cascade Mountains and coastal range. These rivers have created significant floodplain and estuarine wetlands. Along the coast, sand dunes trap freshwater and create coastal lakes, ponds, and palustrine marshes. Important river systems include Nestucca, Siletz, Yaquina, Alsea, Siuslaw, Umpqua, Coos, Coquille, Rouge, and New. In addition to providing important waterfowl habitat, Oregon’s estuaries provide critical rearing habitats for anadromous fish. Losses of 50-80% of intertidal marsh habitat in Oregon’s estuaries have resulted from diking for farmland conversion (Thomas 1983). Several small refuges, including Siletz Bay and Bandon Marsh NWRs, protect critical tidal wetlands, but no large public wetland complex exists.