Tetlin National Wildlife Refuge is a dynamic landscape made up of forest

Forest

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

s, wetland

Wetland

A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

s, tundra

Tundra

In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

, lakes, mountains and glacial rivers bounded by the snowy peaks of the Alaska Range. This upper Tanana River

Tanana River

The Tanana River is a tributary of the Yukon River in the U.S. state of Alaska. According to linguist and anthropologist William Bright, the name is from the Koyukon tene no, tenene, literally "trail river"....

 valley has been called the "Tetlin Passage," because it serves as a major migratory route for birds traveling to and from Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, the lower 48 and both Central

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

 and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. Many of these birds breed and nest on the refuge. Others pass through on their way to breeding and nesting grounds elsewhere in the state. Migrants, including 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, 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....

, swan

Swan

Swans, genus Cygnus, are birds of the family Anatidae, which also includes geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Sometimes, they are considered a distinct subfamily, Cygninae...

s, cranes, raptor

Bird of prey

Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

s and songbird

Songbird

A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...

s, begin arriving in the valley in April, and continue into early June. An estimated 116 species breed on Tetlin during the short summer, when long days and warm temperatures accelerate the growth of plants, insects and other invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s, providing a ready source of rich foods for nesting birds.

Tetlin Refuge also supports a variety of large mammals. Dall sheep

Dall Sheep

The Dall sheep , Ovis dalli, is a species of sheep native to northwestern North America, ranging from white to slate brown in color and having curved yellowish brown horns...

 dot the higher slopes while moose

Moose

The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

 feed upon the tender new growth that springs up in the wake of frequent lightning caused fires. Wolves, grizzly

Grizzly Bear

The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

 and black bear

American black bear

The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

s and members of three different caribou herds range over the refuge.

Two of the six known humpback whitefish spawning areas in the Yukon River

Yukon River

The Yukon River is a major watercourse of northwestern North America. The source of the river is located in British Columbia, Canada. The next portion lies in, and gives its name to Yukon Territory. The lower half of the river lies in the U.S. state of Alaska. The river is long and empties into...

 drainage are located within the refuge. Along with caribou and moose, these fish are important subsistence resources for area residents. Arctic grayling

Grayling (genus)

Thymallus is a genus of freshwater fish in the salmon family of order Salmoniformes; it is the only genus of subfamily Thymallinae. The type species is T. thymallus, the grayling. The genus's five distinct species are generically called graylings, but without qualification this also refers...

, northern pike

Northern Pike

The northern pike , is a species of carnivorous fish of the genus Esox...

 and burbot

Burbot

The burbot is the only gadiform fish inhabiting freshwaters. It is also known as mariah, the lawyer, and eelpout. It is closely related to the marine common ling and the cusk...

 are also found in the refuge's many streams and lakes.

The refuge has a surface area of 700058 acres (2,833 km²), and is one of the larger (currently #18) National Wildlife Refuge

National Wildlife Refuge

National Wildlife Refuge is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the world's premiere system of public lands and waters set aside to conserve America's fish, wildlife and plants...

s in the United States, although, perhaps surprisingly, also the second-smallest of the sixteen in Alaska.