Schiess: The aerial sage grouse count

For 50 years the counting of the dwindling numbers of Greater Sage Grouse has been a bumpy ride across the desert terrain by personnel of the Idaho Fish and Game along with dedicated volunteers. That could soon change as it may mostly be done from the air with aerial infrared (AIR), which reads temperature from high above.

“Over the past six years, researchers at the U. S. Geological Survey, Brigham Young University, Idaho State University and the University of Idaho have been involved in testing this new technique,” said Gifford Gillette, a Wildlife Research Scientist with the Wildlife Management Institute. “This new technique for counting sage grouse on their leks involves a cooled infrared camera mounted to a gyro stabilization unit in a fixed-wing airplane.”

Each year during March and April, male Sage grouse gather on traditional breeding grounds called “leks,” where they display, fight and show-off to the females for the right to breed. Population trends of this, the largest grouse in the world, can be determined by the numbers of them showing up on these grounds through the desert.

“Wildlife biologists often look for trends in data that would indicate whether populations are increasing, decreasing or stable,” said Gillette. In an effort to make this data as accurate as possible, AIR counts are being used alongside the usual ground-based counts “to determine precisely how many grouse are missed by AIR counts and how many are missed by ground-based counts determining if the counts are similar in accuracy.”

This past spring teams of two personnel were sent out to do a ground count of leks with each making individual counts without communicating with each other during the count. At the same time a plane was doing an AIR count. Then both teams would move to another lek to do the same thing there.

Fake or “pseudo leks” made up of captive-raised pheasants are placed in the sagebrush habitat to create a known number of birds to be counted from the air. This will indicate how many of the birds might be missed by the AIR count.

This spring the wildlife research biologists from the Idaho Department of Fish and Game were assisted by Nevada Department of Wildlife, U.S. Geological Survey spanning Idaho and northern Nevada and volunteers with the Idaho Master Naturalist Program.

Ground-based counts or sight-counts have their disadvantages. First, observers have to wait until daylight to do their counts; second, many of the leks are on ridges where birds may be hidden from view during one count and a week later all the birds may be on the far side of the ridge and not counted. A third difficulty deals with traveling from one lek to another quick enough to count it before hawks or eagles flush the birds before they can be counted. The infrared aerial counts, though, can start earlier and be done before daylight; and the plane can get multiple leks very quickly.

“Preliminary results suggest that both methods correctly account for approximately 90% of the sage-grouse at the lek,” said Gillette. “However, it can be a daunting task for biologists to accomplish all of their management objectives during the busy spring months. Counting leks with AIR is just one more tool that biologists can use to meet the demands of managing wildlife species on behalf of Idaho’s citizens.”

As technology continues to be developed, wildlife researchers will have the advantage to do a better job of managing wildlife and specifically help the population of the Greater Sage grouse improve in Idaho.