Nature Tech

Grouse Count: Aerial Infrared Technology Ensures Accurate Wildlife Census

The challenge: find a chicken-sized bird in a million-acre expanse characterized by rugged canyons and bad or non-existent roads.

That’s the reality of monitoring greater sage grouse populations throughout much of their range.

The solution: infrared sensing that revolutionizes aerial grouse censuses — providing a safe, reliable method for counting the birds.

This technology’s application goes well beyond sage grouse counts – it can help researchers find wolves in forested terrain, detect bat caves in remote deserts and even measure the impacts of fire.

Needle in a Haystack

Greater sage grouse have become one of the most-studied wildlife species in the American West. This stems from their well-publicized decline due to habitat conversion, too-frequent fires, non-native weeds, West Nile virus and other factors.

The foundation of sage grouse research – and conservation – is ensuring accurate counts of the birds.

As birds go, they’re fairly big. Each spring, the males gather at display grounds, called leks, where they display for females.

It’s not especially challenging to see grouse when they’re on the lek. But counting them – and counting an entire population – is a whole different ballgame.

That’s what Art Talsma, director of stewardship for The Nature Conservancy in Idaho, tells me.

When Talsma tells me something’s difficult, I pay attention: I’ve been afield with him, as he lopes up steep mountain slopes and dodges striking rattlesnakes. The consummate wildlife biologist, there’s not much Talsma finds difficult.

But to count grouse at a lek, a researcher has to be there before the birds show up – often 3 a.m. From ground level, it can be difficult to assess the exact number of birds without disturbing them.

Once that is accomplished, the researcher must move quickly to another site – traversing rutted roads, deep canyons and thick brush to do so. The grouse quit displaying by mid-morning, so the window is small.

“You would be lucky to count two to three leks in a day,” says Talsma. “And that’s being very, very ambitious.”

Greater sage grouse display in a lek. Photo © Tony Morris/Flickr through a Creative Commons license.
Greater sage grouse display in a lek. Photo © Tony Morris/Flickr through a Creative Commons license.

A 20 Lek Day

That’s why he wants me to meet John Romero, chief pilot and chief of operations for Owyhee Air Research, a firm in Nampa, Idaho that conducts aerial biological surveys. Romero is pioneering a technique that is resulting in much more accurate, reliable grouse counts.

Romero has conducted aerial sage grouse counts for years, with observers counting and video documenting leks. But even that approach had limitations.

“You were flying over the sagebrush, looking for a white dot of a male’s chest,” says Romero. “Standard protocol is to count a half mile away to avoid disturbing the birds. It’s very difficult to get an accurate count from that distance.”

He’d have two to three observers working, flying just 300 to 500 feet above the ground. And still, Romero realized they were undoubtedly missing birds. Missing leks.

Romero used to fly for the military, so he was already familiar with infrared technology. Infrared detects minor changes in temperature, and shows up as different colors on the screen. Even one degree shows as a different color – making it easy to locate grouse (and other wildlife) remotely.

They show up as recognizable (to trained scientists) blobs on leks. Using proper technique, all birds can be counted.

“The first time we flew over a lek, I could see the birds just light up,” says Romero. “I knew right then, this really would work.”

The technology is not cheap; Romero mentions that nerve-wracking first flight when a researcher held a $125,000 camera out the window. But in the long run, it will prove a much more efficient and cost-effective method.

When a lek is located, the crew flies around it, ensuring it is documented from 360 degrees – a bush or rock covers a birds’ heat signature, so they want to make sure every angle is covered.

The resolution is quite high, researchers familiar with grouse can tell right away from bird habits and size.

Lek locations are recorded via GPS and are recounted later in the season, or ground truthed, to ensure accuracy.

It’s fast – a crew will count at least ten leks per day, and often 15 to 20 per day. During March and April last year, the height of the lekking season, the crew counted 250 leks.

“You would have to have a huge number of people on the ground counting to achieve that count,” says Romero. “It would be a staggering amount of work, and probably would disturb the birds, too.”

Using the infrared, the air crew can easily count from a distance, and also high in the air to ensure crew safety.

The sensing camera is mounted on the airplane in way so that it provides stable images, easy for researchers to analyze.

“No matter what the airplane is doing, the video is rock solid,” says Romero. “That’s critical when we’re running transects.”

The technique is being published in the Journal of Wildlife Management and has been enthusiastically embraced by state and federal agencies and conservation organizations as a method to count grouse and other wildlife.

“The infrared sensing provides the data to The Nature Conservancy to inform our decisions on where and how we work in sagebrush country,” says Talsma. “This is big, remote, wild country. We can’t just work everywhere. This allows us to pinpoint areas where we can make the most difference for grouse.”

Later this week: Join us for fun videos of other applications for infrared in wildlife research.

Matthew L. Miller

Matthew L. Miller is director of science communications for The Nature Conservancy and editor of the Cool Green Science blog. A lifelong naturalist and outdoor enthusiast, he has covered stories on science and nature around the globe. Matt has worked for the Conservancy for the past 14 years, previously serving as director of communications for the Idaho program. More from Matthew L.

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4 comments

  1. Thanks for sharing this story, Matt. Based on your video, it looks like it makes a ton of sense to use IR to count grouse. One only wonders why they have waited so long to use this technology for counting leks? Cost, I presume, but it would be interesting to calculate the expense for all the time of wildlife biologists going to leks and counting versus this method. I’ll ask around in Wyoming to see if it is being used here.

  2. Great to hear that IR has proven useful in this scenario, especially given sage grouse are so easily disturbed and the population size has been so difficult to pin-point!

    Compliments on your writing style as well.

  3. yes, relatively much easy. IR works on radiation due to body heat( certain wavelength ).Here counting the bright dots is the total counts

  4. A interesting piece of work!
    How big a size can be detected using this method? Can the little chickens be also seen?