The recently re-established wood bison population that once resided just outside of Anchorage will soon face their first winter in the unforgiving environment of Western Alaska, with the potential to encounter flooding, deep snow and ice breaking underfoot for the first time.
"They don't have that kind of experience," Alaska Department of Fish and Game spokesperson Cathie Harms said.
Over the spring and summer, 130 wood bison were moved from the Alaska Wildlife Conservation Center, near Portage Glacier, to the village of Shageluk -- about 350 miles from Fairbanks -- which acted as the staging area for the bison's release into the Innoko Flats near the Innoko and Yukon rivers. The bison were reintroduced after disappearing from the state more than a century ago, for reasons unknown.
Since their release, 16 of the bison have died. The exact cause of death for seven of the animals is unknown, although Fish and Game has ruled out death by humans or predators. The other nine fell through ice and drowned.
"It's nature," Harms said. "They need to learn a lot more about ice."
Overall, Harms is still hopeful the animals will do well through the winter. They've been adapting quickly and are learning skills they'll need to survive the winter, she said.
When Fish and Game released the animals it was nearly calving season. The department hoped the area where the cows gave birth might provide the herd an anchor location that could prevent them from scattering. It worked, and 15 calves were born.
Some bison have traveled as far as 90 miles away before returning to the land they anchored in.
"They are learning that area," Harms said. "They're figuring out where the shelter is and finding higher ground. They're designed to use their heads to sweep snow and find food under the snow. The more familiar they are with the area, they will know where the best food is."
During the summer the bison swam in the Lower Yukon and Innoko rivers area, and in lakes. Typically, bison are "very strong swimmers," and this wood bison herd is no exception, Harms said.
The wood bison began breeding in late July and continued through August after bulls were delivered to the area by barge and joined groups of cows, Fish and Game education and outreach specialist Mike Taras said.
But how successful that breeding season has been won't be determined until next summer, after the herd's first winter in the wild.