The Copper River Delta Shorebird Reserve Unit near Cordova, Alaska, is an area of great diversity that offers essential habitats for shorebirds and other wildlife from early spring through late fall. The site comprises tidal and submerged lands in Orca Inlet and extensive intertidal and freshwater wetlands, extensive marsh adjacent to tidal channels, and delta and barrier islands near the mouth of the Copper River. Wetland habitats extend from the foot of the Chugach Mountains to the tidal flats inside the barrier islands. Between the mountains and the estuarine area is a belt of sedge meadows, ponds, willow and sweetgale shrubs, and vegetated wetlands bordered with alder and cottonwood along streams.

As many as 1.1 million shorebirds have been observed at one time using the Copper River Delta during the peak migration (April 25 - May 15). Western Sandpipers and Dunlin, the two most abundant species of shorebirds on the Pacific Coast, stop here each year before flying further north and west to their breeding grounds. Their presence on estuarine mudflats behind the barrier sandbar islands is, by far, the most impressive use of Copper River habitats by shorebirds. Obtaining the necessary energy reserves on the Delta greatly influences their reproductive success elsewhere in Alaska and/or Siberia. Important too are the upland marsh wetlands for other shorebird species breeding here.

In addition to stopover habitat, the wetlands on the Delta provide a variety of shorebird nesting habitat. Nesting species include: Short-billed Dowitchers, Least Sandpipers, Greater Yellowlegs, Common Snipe, Red-necked Phalaropes, Spotted Sandpipers, and Semipalmated Plovers. Less common Delta breeders include Dunlin and Lesser Yellowlegs.