The Koyukuk National Wildlife Refuge is a conservation area in
Alaska
Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...
. It lies within the
floodplain
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...
of the
Koyukuk River, in a basin that extends from the
Yukon River
The Yukon River is a major watercourse of northwestern North America. From its source in British Columbia, it flows through Canada's territory of Yukon (itself named after the river). The lower half of the river continues westward through the U.S ...
to the
Purcell Mountains and the foothills of the
Brooks Range
The Brooks Range (Gwich’in language, Gwich'in: ''Gwazhał'') is a mountain range in far northern North America stretching some from west to east across northern Alaska into Canada's Yukon Territory. Reaching a peak elevation of on Mount Isto, ...
. This region of wetlands is home to
fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
,
waterfowl
Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...
,
beaver
Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...
and
Alaskan moose, and wooded
lowland
Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland.
Definitions
Upland and lowland are portions of a ...
s where two species of
fox,
bear
Bears are carnivoran mammals of the family (biology), family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats ...
s,
wolf
The wolf (''Canis lupus''; : wolves), also known as the grey wolf or gray wolf, is a Canis, canine native to Eurasia and North America. More than thirty subspecies of Canis lupus, subspecies of ''Canis lupus'' have been recognized, includin ...
packs,
Canadian lynx and
marten
A marten is a weasel-like mammal in the genus ''Martes'' within the subfamily Guloninae, in the family Mustelidae. They have bushy tails and large paws with partially retractile claws. The fur varies from yellowish to dark brown, depending on ...
prowl.
The Northern Unit of the
Innoko National Wildlife Refuge, commonly known as Kaiyuh Flats, is managed as part of the Koyukuk/Nowitna Refuge Complex. Rich in wetlands, the Northern Innoko is an extremely productive breeding area for migratory waterfowl and fish. The streams and rivers of the refuge complex support three species of
salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native ...
,
Arctic grayling,
sheefish, and many other fish species. Northern
pike, especially those that winter in the shallow lakes of the Northern Innoko National Wildlife Refuge, sometimes grow to record size.
In the Koyukuk's wetlands, breeding waterfowl feast upon water plants and abundant protein-rich invertebrates. Young birds grow quickly in the short, lush summer, and prepare for the fall
migration
Migration, migratory, or migrate may refer to: Human migration
* Human migration, physical movement by humans from one region to another
** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
. As many as 100,000 ducks are hatched and raised on refuge lands during a single nesting season. Migratory songbirds and raptors also depend on the rich resources of the Koyukuk Refuge for breeding and raising young.
Koyukuk Refuge's Three-Day Slough area, part of the Koyukuk Wilderness, has some of the most productive moose habitat in Alaska. This region has, at times, supported more than 10 moose per square mile. Recent counts indicate that some areas still contain densities of five moose or more per square mile. As with much of the refuge big game work, these moose counts are cooperative efforts between the
U.S. Fish and Wildlife Service and
Alaska Department of Fish and Game.
Caribou
The reindeer or caribou (''Rangifer tarandus'') is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, boreal, and mountainous regions of Northern Europe, Siberia, and North America. It is the only represe ...
from the migratory Western Arctic Herd, which numbers more than 450,000, often move into the northernmost reaches of the refuge in winter months in search of lichens that lie beneath the snow. The Koyukuk also supports a resident non-migratory caribou population, the Galena Mountain Herd, which numbers about 300. Wolf packs, Canadian lynx and other furbearers, as well as
black
Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...
and
grizzly bear
The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America.
In addition to the mainland grizzly (''Ursus arctos horr ...
s, are found on the refuge year around.
See also

*
List of largest National Wildlife Refuges
References
Refuge profileRefuge website
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Protected areas of Northwest Arctic Borough, Alaska
Protected areas of Yukon–Koyukuk Census Area, Alaska
National Wildlife Refuges in Alaska
Wetlands of Alaska
Floodplains of the United States
Landforms of Northwest Arctic Borough, Alaska
Landforms of Yukon–Koyukuk Census Area, Alaska