Wildlife & Habitat

swan pair with cygnets

Due to its location in the southeast corner of the interior of Alaska, Tetlin National Wildlife Refuge is home to a diversity of wildlife species representative of the boreal forest region of Alaska, with additional species that are more commonly found further south and east of Alaska in Yukon and northern British Columbia, Canada. The refuge is host to both resident and seasonally present wildlife including 42 species of mammals, 15 fish species, one amphibian, 160 migratory and 30 resident bird species and a large but unknown number of invertebrate species.

For information on specific Refuge mammals, click the links below: Mammals, Birds, Fish Amphibians, and Invertebrates

  • Mammals

    Cow moose and calf along road

    Tetlin Refuge supports at least 42 species of mammals.  Mammal Checklist 

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  • Birds

    Wilson's warbler

    The Refuge provides habitat for 30 resident and 96 migratory bird species that stop and breed on the refuge (Bird Checklist - pdf) and serves as a major migration corridor for 64 more species that migrate through the refuge, entering or leaving interior Alaska. Compared to the rest of interior Alaska, the diversity of landbirds is high because the Refuge is located within a major migration corridor, and a number of species reach their northern range limit here. However, extreme winter weather sends most birds traveling south, leaving only about 30 resident species year round.

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  • Fish

    Catching grayling

    There are 15 species of fish known to occur on the Refuge. Arctic grayling, burbot, lake trout, northern pike, and humpback whitefish are present in refuge lakes and rivers. There are no significant salmon runs in the upper Tanana River drainage. However, small runs of chum salmon and an occasional chinook and coho have been recorded. Rainbow trout are stocked by ADF&G in Hidden Lake near the Alaska Highway. Other less known fish species in refuge waters include longnose sucker, lake chub, slimy sculpin, broad and round whitefish, and least cisco.

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  • Invertebrates

    tadpole shrimp 150x119

    The health of refuge ecosystems is dependent upon the diversity of invertebrates that support plants and wildlife either directly or indirectly. A study of dragonflies on Tetlin Refuge begun in 2008 has documented 23 species. One species collected, the crimson-ringed whiteface (Leucorrhinia glacialis), is an extension of over 1000 miles to the northwest from the northern limits of it’s formerly accepted range. Ongoing studies are examining the phenology, abundance and diversity of dragonflies and damselflies and their importance as a food resource to the rapidly disappearing rusty blackbird. No comprehensive inventory of other invertebrates has occurred on the refuge.


  • Amphibians

    wood frog 150x119

    Only one amphibian, the wood frog (Rana sylvtica) is found in on the refuge. They inhabit a variety of habitats including mixed forests, open meadows,wetlands and tundra, but are commonly found along shorelines. Wood frogs are highly terrestrial, and are only found in water during breeding and early development. Although adults can be as long as 3 inches (7.6 cm), they are frequently smaller. This smooth skinned frog may be brown, tan, grey, or green above, with a uniformly cream colored underside. It hibernates in shallow depressions under layers of dead vegetation. The wood frog is able to survive winter cold by increasing the glucose stored in the cell fluids; the glucose acts as an antifreeze and prevents skin cells from freezing. Recent studies of wood frogs in Tetlin and other National Wildlife Refuges in Alaska have found some of the highest rates of physical abnormalities (missing, shrunken, or misshaped limbs, or abnormal eyes) documented in the published literature. The cause for the high prevalence of abnormalities is unknown, but hypotheses include chemical contaminants, parasites, ultraviolet radiation, predators, extreme temperatures during development, or a combination of these factors.