They serve as a stopover for migratory waterfowl and shorebirds. Plains are inhabited by migratory waterfowl and cranes. The sanctuary also shelters migratory birds such as swallows, martins, wagtails and various waterfowl. Bones of many other animal species were also present, including horses and migratory waterfowl. Elk, deer, black bears, grizzlies, upland birds, waterfowl, and wolves call this area home. They prey on waterfowl, passerines, and migrating birds. Larger sizes are used for hunting larger upland game birds and waterfowl. Bird species include hawks, pelicans, roadrunners, and various waterfowl and oceangoing species. They are capable retrievers for waterfowl hunting. Marshes provide habitats for many kinds of invertebrates, fish, amphibians, waterfowl and aquatic mammals. They provide important breeding habitats for many species of waterfowl. Limited waterfowl habitat exists in certain places. Above the falls, herons, fish eagles and numerous kinds of waterfowl are common. This total includes 102 waterfowl and shorebird species. Seabird migration is similar in pattern to those of the waders and waterfowl.