Program to reintroduce bison to Banff National Park finds 9 out of 10 cows are pregnant

Adult bison near three calves [Credit: Parks Canada]

Nine of out the ten of the bison females living in Banff National Park are pregnant, Parks Canada has announced, meaning that the herd that was introduced into the area in 2017 is growing.

Until last year, Banff National Park had been barren of bison for over a century. While millions of the animals once roamed the plains of North America, they were hunted to near extinction by the late 1800s and were eradicated completely from the area that is now known as Banff National Park.

But in February of 2017, the Government of Canada took the first step to replenishing bison in the area, transferring 16 animals into the park. Ten of these were pregnant females females, and in the spring, ten new baby bison were born, bringing the herd’s numbers to 26. Now, nine of those females are pregnant once again, and this time the calves were conceived in the Banff National Park, something that hasn’t happened in over a century.

bison calf standing in snow
The first bison calf born in Banff National Park in over a century was born on Earth Day 2017. [Credit: Parks Canada]

“We’re really excited,” Bill Hunt, resource conservation manager for Banff National Park, told the

Rocky Mountain Outlook. “Last year’s calves had been bred by mature bulls, and so it’s a bit surprising nine out of 10 cows were successfully bred by these younger bulls. We thought we might have half of that.”

If all of the calves are brought to full term, the new herd’s numbers will grow to 35, although the viability of the pregnancies and the survival of the calves is not a sure thing.

“It’s unlikely to have 100 per cent success,” Hunt said. “We’ll hope for the best, but it wouldn’t be uncommon to lose one or two.”

Bison running into field from shipping containers
Here, the bison are seen moments after their release, charging from their shipping containers towards their new home. [Credit: Dan Rafla/Parks Canada]

This new bison herd was created out of a larger herd still living in Elk Island Park. The 16 original bison were transported in shipping containers on the backs of trucks and transported to a ranch on the edge of the park, and the next morning a helicopter transferred the containers into the park.

The reintroduction is being done as a five-year pilot project. The bison have spent their first year and a half in a “soft-release pasture” where Parks Canada can monitor them, but in July, they will be released into a larger 1,200-square-kilometre zone. After five years, Parks Canada will do a review and assess if longer-term restoration is possible.

Bison herd with calves walking at edge of a river
If all the pregnancies are carried to term, the herd could grow to 35 animals. [Credit: Karsten Heuer/Parks Canada]

“The real challenge will begin once we open the gates this summer,” Hunt said. The bison are wearing satellite collars, which will allow scientists to track them and help steer their movements in the parks, but as these are wild animals in a new environment, no one can predict what they might do.

However, so far, the program seems to have been a success. “Even though the new wild herd has only returned to the Panther Valley since early 2017, they look so comfortable it’s as they’ve been there forever,” the Parks Canada website reads.

“The animals are all healthy and are quickly adapting to their new environment; they are bucking, bedding, grazing, and loving their new mountain home!”

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