BILLINGS, Mont. (AP) — Fewer bison migrated out of Yellowstone National Park this winter than in years past, leading officials to drop plans to capture and remove some of the animals as part of a population control program.

About 170 bison were shot after leaving the park by hunters, down from more than 200 last year, The Billings Gazette reports.

About 260 of the burly animals were shipped to slaughter last year.

Park officials have tried to avoid such slaughters by relocating some bison to Native American tribes.

But the program has had only limited success.

In the past, the bison capture and slaughter program has met resistance from animal rights activists.

Three people protesting the bison capture in Yellowstone three years ago pleaded guilty to misdemeanor charges and were banned from the park for five years.

Cody Cyson of Minnetonka, Minn., and Thomas Brown of East Hardwick, Vt., pleaded guilty to entering a closed area in the park after chaining themselves to a squeeze chute and interfering with an agency function. Hanna Ponder of Donnelly, Idaho, pleaded guilty to one charge of entering a closed area near the Reese Creek drainage of the park.

They belong to an advocacy group called Wild Buffalo Defense. They were arrested near the park's Stephens Creek Capture Facility on March 6, 2018.

Get our free mobile app

10 Absolute WORST Tourist Incidents at Yellowstone National Park

NEXT UP: 10 Absolute WORST Tourist Incidents at Yellowstone National Park