Lewis and Clark National Wildlife Refuge, near the mouth of the Columbia River

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

, provides wintering and resting areas for an estimated 1,000 tundra swans, 5,000 geese

Goose

The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....

, and 30,000 duck

Duck

Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...

s. Other species include shorebirds and bald eagles.

Estuary

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 waters provide vital food resources for juvenile salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 as they pause to become acclimated to salt water before entering the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. Bald eagles are present year-round; there are 30 to 35 active nest sites.

Other fish species using the estuary include American shad

American shad

-Introduction:The American shad or Atlantic shad, Alosa sapidissima, is a species of anadromous fish in family Clupeidae of order Clupeiformes. It is not closely related to the other North American shads...

, smelt, perch, starry flounder

Starry flounder

The starry flounder is a common flatfish found around the margins of the North Pacific.The distinctive features of the starry flounder include the combination of black and white-to-orange bar on the dorsal and anal fins, as well as the skin covered with scales modified into tiny star-shaped plates...

, bass

Bass (fish)

Bass is a name shared by many different species of popular gamefish. The term encompasses both freshwater and marine species. All belong to the large order Perciformes, or perch-like fishes, and in fact the word bass comes from Middle English bars, meaning "perch."-Types of basses:*The temperate...

, catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

, and Pacific lamprey

Pacific lamprey

The Pacific lamprey is an anadromous parasitic lamprey from the Pacific Coast of North America and Asia. It is also known as the three tooth lamprey and tridentate lamprey.-Biology:...

. Harbor seal

Harbor Seal

The harbor seal , also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere...

s use sandbars and mud flats as resting sites at low tides, while seal

Pinniped

Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

s and California sea lion

California Sea Lion

The California sea lion is a coastal sea lion of western North America. Their numbers are abundant , and the population continues to expand about 5% annually. They are quite intelligent and can adapt to man-made environments...

s feed on fish in the estuary. Beaver

Beaver

The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...

, raccoon

Raccoon

Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

, weasel

Weasel

Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....

, mink

Mink

There are two living species referred to as "mink": the European Mink and the American Mink. The extinct Sea Mink is related to the American Mink, but was much larger. All three species are dark-colored, semi-aquatic, carnivorous mammals of the family Mustelidae, which also includes the weasels and...

, muskrat

Muskrat

The muskrat , the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful animal over a wide range of climates and habitats...

, and river otter also live on the islands.