Where Wild Bison roam: Radio collars signal movements at Old Man on His Back Prairie and Heritage Conservation Area
It’s a breathtaking sight that harkens to a bygone era of Canadian history – wild plains bison roaming a wide open prairie landscape. On the Nature Conservancy of Canada’s Old Man on His Back Prairie and Heritage Conservation Area (OMB) the movement of bison across Saskatchewan’s grasslands doesn’t just paint a pretty picture, thanks to modern technology it also provides data critical to the study and conservation of these rare creatures and their grazing lands.
Managed as a working ranch, NCC’s 13,088- acre (5,296-hectare) OMB property is a mix of leased and deeded Crown land, partially purchased by NCC in 1996, with the balance of the land generously donated by former landowners Peter and Sharon Butala. Located in the so-called “South of the Divide” area of Saskatchewan, OMB and surrounding large blocks of native prairie are primarily operated as community pastures. They represent some of the largest intact blocks of high quality grassland located in the province and form part of a key corridor for wildlife and species at risk in the Northern Great Plains of North America.
The Butalas’ vision was to see plains bison restored to their native habitat – a goal and wish that NCC fulfilled with its introduction of 50 head of plains bison from Elk Island National Park to the property in 2003, and the herd’s subsequent management by NCC staff. An initiative now underway to use GPS-enabled radio collars to track the bison’s movements is expected to further enhance NCC management efforts.
Former NCC staff member and current graduate student Dale Gross is working with fellow University of Saskatchewan (U of S) graduate student Hannah Hilger to use radio collars to track both cattle and bison. Their work at OMB serves not only NCC’s wildlife and habitat conservation efforts, but information shared with ranchers and other land managers will also provide these industry partners with valuable insights into bison and cattle grazing patterns and their preferred natural fodder.
Influencing animal grazing patterns
With bison roaming an expansive 5,900-acre (2,388-hectare) pasture, the radio collars are expected to enhance both the tracking of the animals and land conservation efforts.
“We usually have about 140 animals with calves. About 80 of them are adults that we have to track over a large area. They display similar grazing patterns year after year, just like humans do; when you go to your regular restaurant, you’ll have a favourite booth that you like to sit at and a favourite food to eat - bison are the same way,” explains Gross. “Our research helps us to establish what those patterns are. We can then use experimental treatments to see if we can change that pattern, so the same areas don’t get overutilized, and we can offer more variety of habitat.”
To encourage alternate grazing patterns, Gross and his colleagues try a number of techniques that aim to attract bison and cattle. While a combination of salt licks and watering holes are traditionally used to attract cattle, research has also shown that they also prefer grass re-grown after a fire. As a result, Gross and his colleagues will conduct controlled five- to 15-acre burns on the land to entice grazing animals. Research has shown that bison and cattle are attracted to nutrient-rich re-growing grass areas, and the animals will move to these areas on their own which allows other pastures to recover from grazing.
“We know where the salt and water is, so [the radio collars allow us to] see how much time they spend at those areas. And we can see what best attracts them – is it re-grown grass, water, salt or certain minerals? Once we’ve established what they like, we can move the animals around to places they seem to be avoiding or don’t normally go by making the food source in these places more attractive to them,” explains Gross.
They will share any data they find with area ranch managers to help them control the location of their own grazing animals, which can lead to higher productivity and weight gains. It will also be shared with anyone across the Northern Great Plains interested in using fire as a land management tool. “Managing land in a manner to which native species have become adapted should allow the most amount of species to survive and thrive,” says Gross.
Radio collar considerations – from comfort to battery life
For NCC researchers, tracking the locations of bison on the property formerly involved time-consuming and sometimes challenging walks or drives, particularly when some animals were skittish. Radio collars, which Gross and Hilger will fit onto bison for the first time at OMB in December 2017, are expected to make data gathering less of a trial.
The Lotek-brand GPS radio collars the U of S uses are not only comfortable for animals to wear, but also convenient for researchers to use. The collars will provide information to NCC staff working in the field or at their desks.
Since the team won’t have the opportunity to replace the batteries in the collars once they are on the animals, it is important to program the collars in a way that conserves battery life.
“The more often you take a reading, the more battery life it uses, so you have to balance it out,” says Hilger.
Computer models, and past experience with cattle, helped Gross and Hilger determine the best scenario for collar battery life. In previous tests, cattle wore radio collars for five months, with readings taken every 15 minutes. To gather sufficient data on bison movements, the bison will have to wear collars for a full year. As a result, Gross and Hilger will take readings every 20 minutes in order to conserve the collar batteries.
Wrangling collars onto bison
Unlike cattle on the ranch, prairie bison are wild animals. A group of U of S researchers, NCC staff and volunteers, and local ranchers are planinng to take advantage of the annual bison roundup at OMB to fit the animals with radio collars.
The roundup will take place in early December, when temperatures are cold enough that watering holes are frozen and food is limited, and bison are thereby more easily enticed by offerings to get then to the corrals. Once in corrals, the bison will be separated into smaller herds and processed through handling facilities, where the collars will be fitted.
Once the collars are on, the bison will resume freely roaming the huge pasture, with Gross and Hilger monitoring their locations and gathering data to help NCC researchers and industry partners sustainably manage their land and herds.
Learn more about the plains bison at OMB >