Bison turn back the clock on a patch of prairie

A baby boom hits a herd in a remote Saskatchewan national park, an area that hasn't felt bison hooves in more than 120 years

DAWN WALTON

May 19, 2009

CALGARY -- In a remote part of the already remote Grasslands National Park in the southwest corner of Saskatchewan, a herd of plains bison is in the midst of calving season with another bumper crop of babies.

Three years ago, 72 pure-blooded animals were introduced to the 181-square-kilometre refuge as part of a Parks Canada initiative to bring large herbivores to an area that hasn't felt bison hooves in more than 120 years.

Now, that little herd has become prolific beyond expectations.

"I've looked at bison populations across North America during my career and I've never seen a population adapt as well to a system as this one has," said Wes Olson, who oversees the herd for the park.

"Traditionally, when you introduce new animals into a new landscape, their first calving system is around 60 calves per hundred cows. Last year, we had 90 per 100 cows. Every breedable female was bred and successfully carried those calves all winter," he added.

There are now 115 animals grazing the prairie, with 40 calves expected this spring. A projection that the park would be home to 300 to 350 animals in the next five years is way ahead of schedule.

Officials and ecologists say the bison baby boom is nothing short of remarkable. The reintroduction of the animals was to be a symbolic gesture to restore a species nearly wiped off the continent to one of the few grassland habitats left in the country. Now, it's as though the bison are turning back the clock - at least on this little patch of prairie.

Experts estimate that 30 to 60 million bison once roamed the continent. Bison were the lifeblood of aboriginal peoples, but when European settlers arrived, habitat was destroyed and the animals were arbitrarily killed and overhunted to feed demand for hides. The animals vanished in Canada, while about 200 survived in the United States - all in private herds, said Cormack Gates, a professor at the University of Calgary and co-chair of the World Conservation Union's bison specialist group.

He now counts about 431,000 bison in North America thanks to conservation efforts. But most are commercially farmed and bloodlines are muddied with cattle genes. There are few pure bison, wild or semi-wild herds and so-called "conservation herds," which are managed in the public interest by ecological groups or governments, he said.

The animals in Grasslands were shipped as two-year-olds from Elk Island National Park near Edmonton, where Mr. Olson was based for 25 years. The youngsters acclimatized in a paddock before stepping beyond the gate where they had to learn how to behave like bison without guidance from adults.

"When they were released they were kind of like school kids," said Adrian Sturch, manager of resource conservation at the park. "They all kind of hung together in one group. Now, their herd dynamics are starting to take place."

The bulls group together in winter. The cow-calf herd split in two. The animals have started exploring their range. They have also discovered buffalo wallows, large pockmarks on the landscape, that hadn't been used since the 1800s. They roll in them to cover themselves with dust and mud as a natural insect repellent.

The landscape is changing in other ways and so is the wildlife. Officials hope endangered and threatened species will one day thrive.

Grass is being grazed in lengths ranging from barely picked through to golf-course groomed greens. Songbirds are lining their nests with shed bison fur, an ideal material for protecting fledglings from the cold and rain. The chicken-like sharp-tailed grouse has been dusting itself in buffalo wallows and using short green lawns as leks, or mating areas. Ideally, the endangered greater sage-grouse, known for its elaborate courtship rituals, will follow suit. There's also hope the new landscape will be hospitable to struggling birds, including the Sprague's pipit, long-billed curlew and burrowing owl.

This summer, university students will study how the bison have affected songbirds in the park. Remote sensing is being used to assess grazing. Radio collars are tracking where the bison spend their time.

The herd is still too small to be considered viable, according to experts, and Parks Canada acknowledges more research needs to be done. Still, officials are overjoyed with how the bison - and the prairie - are adapting.

"The thing we're witnessing here is genetically driven, deeply ingrained in their psyche and in the landscape," Mr. Olson said. "It's remarkable."

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A small herd of plains bison have been reintroduced to Grasslands National Park.

BISON BY THE NUMBERS

The newly introduced bison are breeding more successfully than hoped. Calf numbers for every 100 cows:

Traditionally: 60

Last year: 90

Bison once ranged in the millions of animals:

Wood bison: 100,000-200,000

Plains bison ; 30-60 million

Bison were nearly wiped out in the 1800s. There are now more than 400,000 in North America.

SPOT THE DIFFERENCE

Plains bison (Bison bison bison)

Descending contour

Yellow ochre cape

Horn often covered by dense hairs

Skirt chaps

Larger beard

Wood bison (Bison bison athabascae)

More abrupt change of contour

Horn clear of hair cover

Hair on forehead lower and longer

Absence of chaps

NINIAN CARTER/THE GLOBE AND MAIL

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