Skip to content

Estimated growth of Aishihik bison herd in southwest Yukon exceeded expectation

Additional survey needed, but biologists report estimated 1,951 animals in herd
A biologist marks bison from a helicopter using a paintball gun somewhere in the Aishihik herd’s range. Later surveys spotting the marked and unmarked bison have led biologists to an ecouraging estimate of the herd’s growing population. (Courtesy/Yukon government)

A summer 2022 survey of a south-Yukon bison herd shows a sizable population and indications that the number of animals may have boomed since the last full survey.

The Yukon government’s department of environment recently made the results of its survey of the Aishihik Bison herd public. The aerial survey conducted last June and July is the first since 2016 to result in a complete population estimate for the herd. Less thorough counts to ensure the bison population was above certain thresholds to inform management decisions were undertaken in 2020 and 2021.

Government biologists estimate the size of the herd at roughly 1,951 animals. This is a significant increase over the 2016 population estimate of approximately 1,325 bison. This would amount to a 47 per cent population increase in six years but the report on the bison population suggested the possibility of an overestimate. It noted that a standard forecast based on the 2016 estimate would only have led to an expected 1,701 animals in 2022. Another full survey this summer or next year is being reccomended to confirm the accuracy of the 2022 numbers.

Last summer’s survey concluded there were at least 857 adult bison and 135 calves alive in the sizable survey area in the southwest corner of the territory.

Focusing on areas where bison fitted with GPS tracking collars were known to be and other areas the herd is known to use during the warm months, the government biologists conducted a “mark-resight survey.”

This consisted of marking bison using a paintball gun from a helicopter and then conducting later surveys to count the number of marked and unmarked bison. Marking efforts tagged 122 bison and then three surveys were flown to locate them.

The Aishihik bison herd is a popular target for harvest by Yukon hunters. A 2021 government report on hunter effort targeting bison in the territory found that over 2,100 hunters bought a bison seal for the 2020/21 hunting season and the total number of bison harvested by Yukon resident hunters was second only to moose during that season.

That same report retells the history of the Aishihik bison herd, which was reintroduced into the southwest Yukon between the late 1980s and early 1990s as part of a nationwide effort to restore bison to their native range after they were nearly driven to extinction across North America more than a century ago. That reintroduced population of 170 animals have multiplied to become the Aishihik herd of today.

Although the Aishihik bison population is rising, woodland bison remain a threatened species existing in only a fraction of its former range. The Aishihik herd is one of only 14 isolated populations of wood bison on earth that range freely.

Contact Jim Elliot at

Jim Elliot

About the Author: Jim Elliot

I’m a B.C. transplant here in Whitehorse at The News telling stories about the Yukon's people, environment, and culture.
Read more