Changing Planet

Photos: 10 Years After Reintroduction, Bison Counters Take to the Skies

A creek canyon divides a group of bison that are busy enjoying the green grasses of spring. (Photo by Kestrel Aerial)

There isn’t a road map for building a vast conserved landscape in today’s world—and there definitely isn’t a path for growing the nation’s largest conservation herd of bison. This year marks 10 years of bison restoration on American Prairie Reserve. We brought them back to the region after a 120-year absence, starting with just 16 animals from Wind Cave National Park in 2005.

Over the years, we’ve also opened up more and more land for the herd to roam on Montana’s plains, and the bison now graze across 31,000 acres in an area of the reserve called Sun Prairie. In a place this big, keeping count of the herd, especially since we have a hands-off approach, means that the team has taken management to the skies.

By Damien Austin

Twice a year, the pilot of a small Super Cub airplane picks me up for aerial surveys over the Sun Prairie region. There, a herd of bison has hit a point in their growth curve that makes me sweat. The 16 animals that arrived on American Prairie Reserve on a rainy night a decade ago have transformed into a herd of hundreds thanks to additional imports from Canada’s Elk Island National Park and an incredible reproduction rate.

From the air, I get a better view of the animals as they spread out across an undulating and surprisingly tricky prairie landscape. (We also track their movements thanks to radio collars on lead females.) Wintertime surveys should be the easiest since the contrast of 2,000-pound animals against white snow gives me a head start. Last year, however, the herd was amassed in two large groups and the red-headed calves sneakily hid among their mothers. I ended up taking a series of photos that had to be printed out in large format and glued together in a collage of fur and feet. It’s not an exact science when you’re trying to sort out shadows and extra legs.

Observing a group of bison from the air. Photo by Gib Myers/APR
Observing a group of bison from the air. (Photo by Gib Myers/APR)

Springtime counts, like the one I just completed, are timed just before new calves are born. Unlike the winter survey, the herd tends to be broken up in smaller groups this time of year as the animals get ready for calving season. Family groups emerge, and I often spot mothers and daughters together as well as groups of females that were imported at the same time. One group really caught my eye this yearthe females from the 2014 bison import from Elk Island were all together with the addition of a single adult female and still-red young calf that must have been born in late fall. Family dynamics are becoming more and more interesting as the herd grows!

A group of the reserve's bison, including tiny copper-colored calves, spread out across the prairie. Photo by Kestrel Aerial
A group of the reserve’s bison, including tiny copper-colored calves, spread out across the prairie. (Photo by Kestrel Aerial)

The survey starts at the western perimeter and we fly 200 feet above the ground from north to south. When we reach a boundary, the plane loops around and moves over by a half mile for the next sweep. If the terrain is difficult, like around creeks, we’ll zigzag around at quarter mile swaths, all the while keeping a tally of animals in each group.

Bison charge across the landscape with observers overhead. Photo by Gib Myers/APR
Bison charge across the landscape with observers overhead. (Photo by Gib Myers/APR)

This year’s count went wellit’s hard to believe that 16 animals have transformed into a herd of 450. And it’s even more exciting to announce that the dozens of calves born since the April survey have now pushed the herd past the 500 mark! By the time the fall count comes around, I’m guessing we’ll pass the 600 mark, too.

It sure feels like we’re heading in the right directionand hopefully carving out a path for others to follow.

A 2015 newborn calf on American Prairie Reserve
A 2015 newborn calf on American Prairie Reserve. (Photo by Dennis Lingohr/APR)

American Prairie Reserve (APR) is assembling a world class wildlife reserve in northern Montana, with the goal of one day creating a seamless 3.5-million-acre grassland ecosystem. APR’s President Sean Gerrity is a National Geographic Fellow, and Damien Austin serves as Reserve Supervisor. Learn more about the Reserve, including bison restoration, on the Reserve’s website

Read All Posts by Sean Gerrity

American Prairie Reserve (APR) is assembling a world class wildlife park in northern Montana, with the goal of one day creating a seamless 3.5 million acre grassland ecosystem. Learn more about APR, including our bison restoration efforts and how to visit, on the Reserve's website.

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