Bison
Along the Iditarod Trail
Bison
resting on a gravel bar of the Tatina River in the summer
BLM photograph
All Rights Reserved. |
A wild self-sustaining
herd of American bison (Bison bison) is located near Farewell, Alaska.
North American bison also known as Wood bison (Bison bison athabascae)
were once part of the native Alaska fauna. These bison became extinct
in Alaska only a few hundred years ago. The reason for this relatively
recent extinction is not known for certain. Some scientists have suggested
that it might have been caused by over hunting by early humans and/or
changes in the bison's habitat. Wood Bison can still be found in some
areas of Canada.
Bison
Return to Alaska
The Farewell area bison herd descends from 17 animals which were
transplanted from Montana to the Delta River area of Alaska in 1928.
In 1965, 18 bison from the growing Delta herd were transplanted
to the Farewell area. The Delta herd has also provided animals for
a third transplanted Alaskan herd located along the Copper and Chitina
Rivers.
Bison near running water along the South Fork of the Kuskokwim
River
BLM photograph
All Rights Reserved. |
In 1968, another
20 bison from the Delta herd were added to the Farewell herd which
by then had increased to about 45 animals. By 1971, the Farewell herd
had grown to around 70 bison. Because available bison range was so
limited, a permit hunt was held by the State of Alaska in 1972 to
help control the size of the Farewell herd. Controlled permit hunts
have been periodically conducted since then to limit bison numbers.
This has been done to avoid any potential damage which might be caused
by bison overgrazing their habitat. The Farewell bison herd currently
has about 300 animals. What
Bison Eat
Bison are large grazing animals or herbivores that migrate between
summer and winter ranges. In the Farewell area, the bison's summer
and winter ranges are about 30 miles apart. Bison can efficiently
use a wide variety of vegetation for food. Bison normally eat grasses,
sedges, forbs, and herbs. Biologists have discovered that Farewell
area bison will also eat leafy succulent new growth of shrubs such
as willows during summer and fall, before the new growth becomes
dry and woody.
Bison herd moving along the South Fork of the Kuskokwim River
BLM photograph
All Rights Reserved. |
The bison's preferred
food or forage of grasses and sedges grows in open sunny areas located
on exposed river bars, in dry stream channels, or along shallow lakes
and streams. Small patches of grasses, sedges, forbs, and herbs are
also located on numerous sand and gravel bars located in braided river
channels. During the long daylight hours of the short cool Alaskan
summers, bison move slowly as they eat or graze. See the summer photographs
of the Farewell area bison below. Bison
in Summer
The mountains of the Alaska Range west of Rainy Pass restrict the
Farewell bison herd's summer range to deep narrow valleys along
the Tatina River and the South Fork of the Kuskokwim River. These
two rivers are located near the Rohn Cabin along the Iditarod National
Historic Trail. Bison migrate to the head waters of these rivers
to avoid hordes of biting insects.
Dark colored adult bison with lighter colored calves
BLM photograph
All Rights Reserved. |
Summer is when
forage is most plentiful and bison put on weight and add layers of
fat to their bodies. Bison calves are usually born in May with short
coats of light reddish hair. Calves can stand and can keep up with
adults very shortly after they are born, which is essential to their
survival. Adult bison have much longer, coarser, and darker hair on
their heads, shoulders, and front legs. See the photograph below.
Predators
Bears and wolves often hunt for bison calves, but are seldom successful.
Adult bulls and cows will charge predators to protect calves. Predators
usually leave adult bison alone, unless they become isolated from
the rest of the herd or are sick and weak. Adult bison are large,
formidable, and are usually too difficult to kill.
Bison
in Winter
Alaskan winters are very harsh and difficult for most animals to
survive. During winter, the bison migrate to their winter range
located northwest of Farewell Lake. This winter range is located
on flat glacial out wash plains or deposits called moraines. These
moraines are interspersed by wide braided river flood plains of
the Middle, South, Windy, and Pitka Forks of the Kuskokwim River
and by the smaller Salmon, Bear, and Sheep Creeks. The bison's winter
habitat includes river flood plains, dry glacial lake beds, and
frozen shallow lakes and ponds.
Bison are naturally
adapted to withstand fierce winter winds and cold temperatures.
A combination of thick layers of hair, stored fat, and plenty of
dry grasses and sedges will usually insure the survival of healthy
bison through winter. Bison are able to smell and locate their winter
food even if it lies under deep snow. Their massive heads and shoulders
can then be used as "snow plows" to push aside the snow
to expose any dried grasses and sedges.
Bison
and Wind
BLM and State of Alaska wildlife biologists believe that the Farewell
herd has been successful due, in part, to the presence of strong
winter winds. In these areas, winds can sweep along river beds and
across open areas and help to keep them free of deep snow. This
makes it much easier for the bison to find forage to eat during
the long and dark Alaskan winters. The bison do not have to expend
as much energy in wind blown areas to find food and this helps them
to conserve precious energy during the long periods of bitter cold.
Bison
and Fires
Biologists believe that wild fires which occurred along the South
Fork of the Kuskokwim River in 1977 and 1990 helped to improve the
herd's winter habitat. The fires killed trees and shrubs and created
habitat which became more favorable to grasses and sedges. Biologists
have conducted studies which have shown that the Farewell area bison
were able to expand their winter range into these burned areas.
Fire burned areas did not retain as much deep snow as unburned areas.
Within about ten years, old fire burned areas will gradually have
trees and shrubs growing back. This reduces the amount of available
bison habitat, unless fire periodically burns the area.
Note
on References:
Most of the above information comes from professional
papers prepared by Bureau of Land Management (BLM) and State of
Alaska Department of Fish and Game (ADF&G) wildlife biologists
in 1983 and 1985. If you use any of the above information, please
credit both BLM and ADF&G as original sources and provide complete
references to the original professional wildlife reports. You may
request copies of these professional reports by contacting a wildlife
biologist in the BLM
Anchorage Field Office or by downloading PDF versions below.
Click once on
the text below to download a PDF version of the professional wildlife
papers or reports,
- Winter Diets
and Habitat Use of An Alaskan Bison Herd After Wildfire, 1983
by Bruce Campbell and Mike Hinkes, 110 KB in size -- Click
Here
- Summer and
Fall Browse Utilization by An Alaskan Bison Herd, 1985 by Van
Waggoner and Mike Hinkes, 29 KB in size -- Click
Here
Other
links:
- State of
Alaska Department of Fish and Game (ADF&G) American Bison
web page -- Click
Here
- ADF&G
Delta Junction State Bison Range web page -- Click
Here
- Prehistoric
Steppe Bison information; Yukon Beringia Interpretive Centre,
Whitehorse, Yukon, Canada -- Click
Here
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