Bison begin migrating out of Yellowstone National Park

BOZEMAN, Mont. (AP) — Bison presence outside of Yellowstone National Park remained low during the last weeks of Montana's bison hunting season, but the herd's annual migration and hunter activity recently picked up.

Morgan Jacobsen, a spokesperson for Montana Fish, Wildlife and Parks, told the Bozeman Daily Chronicle that on Thursday that wildlife managers have seen some bison make their way out of the park over the last week. Two bison — a bull and a cow — were recently taken by tribal hunters, he said.

In the last week, park officials have observed a herd of approximately 250 animals gather around the Roosevelt Arch on the boundary of the park near Gardiner, Jacobsen said. A handful of animals were seen outside of the park.

Few bison were observed west of the park over the last seven days.

Buffalo Field Campaign, a conservation group that advocates for ending the annual bison cull, regularly tracks bison movements. The group reported on Thursday that at least three bison had been taken by hunters since the weekend, and another five were killed at Beattie Gulch on Wednesday.

"Most of the buffalo in the basin, however, have been dodging bullets and staying alive," group members wrote.

Approximately 350 to 370 bison were between Mammoth Hot Springs and the north boundary of Yellowstone, and around 70 bison were seen outside of the park on Tuesday, Tim Reid, the bison program coordinator at Yellowstone, said at the time.

Department officials watched more hunting parties travel toward Gardiner and West Yellowstone just before the state's hunt ended on Feb. 15. The efforts were to little avail, as bison were largely still within the park, according to Jacobsen. The state hunt ran from Nov. 15 to Feb. 15.

Bison tend to migrate outside of the park when there's a significant weather push, but this year's frequent cycling between low and high temperatures has delayed the migration, Jacobsen said.

In total, state hunters killed six bison to the north and 10 bison to the west of the park. Four of the six successful kills to the north filled backcountry tags. Those tags were for an early bison hunting season that ran from Sept. 15 to Nov. 15 in the Absaroka-Beartooth Wilderness.

Yellowstone bison migrate to lower elevations outside of the park to find food each winter. Once they leave the park's borders, they can be killed by hunters or trapped at the Stephens Creek Capture Facility near Gardiner. Bison trapped at the facility are either enrolled in Yellowstone's brucellosis quarantine program or slaughtered.

Reid said no bison will be enrolled in the quarantine program this year, as no space is available.

Annual trapping of bison hadn't started as of Tuesday, but wildlife managers are hopeful they can complete those operations by the end of March — when calving season begins, Reid said.

In December, officials set this year's bison culling recommendations at 500 to 700 animals. An additional 200 male bison could be captured or hunted later in the winter if the initial target numbers are met. Wildlife managers estimated there were around 4,730 of the animals in the park in October.

Federal, state and tribal officials who are part of the Interagency Bison Management Plan set the annual cull numbers. Removing a recommended number of bison each year is meant to manage populations within the park while preventing spread of the disease brucellosis from bison to livestock.

There has never been a documented case of the animals transmitting the disease to livestock in the wild.

Tom McDonald, wildlife division manager for the Confederated Salish and Kootenai Tribes, said the tribes' members hunted six bison around West Yellowstone this winter. Most were bulls. CSKT's hunting season ended in January.

Bison migration patterns have slowly shifted over time, according to McDonald. Those changes have likely been in response to climate change, wildfire impacts on the park's internal habitat and shifting dynamics between the park's two herds.

Reid said Montana's state hunt is a small part of reaching bison removal recommendations, as the season's structure typically doesn't align with the herds' annual migration.

Most successful harvests come from tribes that hunt outside the park boundary on its west and north ends, he said. Some tribal seasons carry into March or April.

"We're just entering the migration period," Reid said. "It all depends on the way the winter lays itself out. That's an uncontrollable variable."

Cold temperatures and a dense snowpack can catalyze migration, according to Reid.

"The migration has started, and we'll see how it plays out," he said. "We have four to six weeks of operational time here to try to stitch together progress toward a removal."