MILL CREEK METROPARKS - Many people living in and around Mill Creek Metroparks were stumped about a low-flying plane they saw over the weekend. 

Some told 21 News it circled their homes for hours, inducing some concern about what it could be. After speaking with the park and the plane company, 21 News learned it has to do with the park's deer population.  

Mill Creek MetroParks are again using infrared technology to count the number of deer occupying the park.

"I could be [surveying] anywhere from 1200 to 1500 feet," explained Mike Holthouse with Above All Aerials.

Hundreds spotted a low-flying plane this past weekend conducting a repeat survey as part of the deer management plan. This comes as dozens of deer have been culled since the fall of 2023.

"In order to get the resolution that we need, we have to fly pretty low, and our line spacing is pretty close together," Holthouse added. "So, from the ground, it looks like we're flying over your house five times in a row."

Mill Creek Proper, Sebring Woods, and Springfield Forest surveyed most of the acreage.

"If I see something that could be a deer, I back up, adjust the temperature ranges, decide if it's a deer or not," Holthouse explained. "If it's a deer, I'm plotting the location on Google Earth."

The company uses infrared technology that captures 15 frames per second. Then, deer are tracked manually, meaning no AI is involved in counting the deer. The accuracy is about 85%, the most accurate out of all other forms of population tracking. Holthouse ensures the count is fairly accurate.

"There's certainly the possibility that I could count something twice," he explained. "But there's an equal possibility that a deer could be in the next line over, then he runs to the line that I'm in after I pass, and I miss it. It's kind of a wash to whether you double count one."

This second wave of surveys comes almost years after the first wave of testing, revealing an average of 387 deer per square mile. The park continues to work towards reaching the average sustainability rate of 10 to 20 deer per square mile.

The company will come back in a few weeks to complete the survey. It should take several months to analyze those final results.