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Copper River Delta — Critical Habitat Area
Fish and Wildlife


Each spring, an estimated 12 million shorebirds, the largest gathering of shorebirds in the western hemisphere, stop along the shores of the Copper River Delta on their way to more northern nesting grounds. Among these migrants are nearly the entire Pacific coast population of dunlins and western sandpipers, and large numbers of least sandpipers, knots, and short and long-billed dowitchers. During peak migration periods from late April through May, concentrations of up to 250,000 shorebirds per square mile have been observed feeding on the Copper River Delta tideflats. Millions of ducks, geese, and swans, including white-fronted and Canada geese, pintails, green-winged teal, American wigeon, shoveler, greater scaup, common and Barrow's goldeneye, long-tailed ducks, bufflehead, and trumpeter and tundra swans, rest and feed on the delta during spring migration. Despite the six-foot uplift of the delta's wetlands during the 1964 earthquake and the resulting drying of some lands, the delta remains a productive summer nesting habitat for thousands of waterbirds, including a major portion of the world's population of dusky Canada geese; over ten percent of the world's trumpeter swans; dabbling ducks; mergansers; and red-throated loons.

Arctic terns, mew gulls, dowitchers, and northern phalaropes are common nesters. Aleutian terns can also be found nesting on the delta. As summer wears on, bald eagles and gulls can be found feeding on spawned-out salmon. Late summer and fall bring the mass southward migration of shorebirds, waterfowl, cranes, raptors, and passerines.


In the spring when new vegetation first appears, brown and black bears descend from the surrounding hills to feed on grasses, sedges, horsetails, and herbs. Brown bears remain on the delta throughout the spring and summer to feed primarily on vegetation, but also on moose calves, waterfowl eggs and young, spawning eulachon, salmon, berries, and wild fruit. Moose were first introduced to the Copper River Flats in 1949 and have thrived in the expanding shrub habitats. The delta provides moose with critical early spring vegetation and calving areas. Willows, herbs, grasses, and aquatic pond vegetation of the delta provide good feeding areas throughout the summer. The beaches and aquatic habitats of the delta provide productive foraging for weasels, mink, wolverine, land otter, muskrat, and wolves. Marten and porcupine can also be found. The highly visible signs of beaver are evident in many drainages of the delta where they attain some of the greatest densities found in North America. Harbor seals haulout and pup on barrier island bars, feeding on salmon and eulachon returning to the Copper River. Gray, minke, humpback, and killer whales, Dall and harbor porpoise, and sea lions feed in the waters of the critical habitat area.


The Copper river system supports large runs of five species of Pacific salmon and their associated commercial fisheries. Copper River kings (chinook) and red (sockeye) salmon are highly prized for their quality and early arrival in west coast markets. Steelhead trout, whitefish, lamprey, cutthroat trout, Dolly Varden, and eulachon are also found in the Copper River system.