They use thermal imaging on the drones. It doesent matter how thick an area is if the deer is there the drones find it. I was watching the video on it. Very interesting.

The drone being used would have a thermal IR camera with zoom. It would be a DJI M30T. The odds of finding the deer are very good with IR. Brush and all that will not matter as much when flying at night using IR. Turtledale they say the deer will still emit enough thermals 48hrs after the shot. I know people could use a dog but then all that traffic going thru your property will definitely disturb the deer more than what the drone would do. With the drone you can just walk straight into where your deer is instead of grid searching by foot.