There have been a number of reports on how deer respond to the rifle season. All show changes in deer movements in response to the hunter pressure. Deer knew there was something amiss and altered their movements right before and during the rifle season. It’s fun making movies of their movements, and the movies are even more fun to watch. Those posts generated a lot of discussion, but there isn’t much that can be said from a scientific perspective. A single deer and an opinion do not research make.
But many deer and a complex statistical model do! Are there larger patterns at play? Katie Gundermann, a graduate student at Penn State University, dug deep looking for those larger patterns in her research for her M.S. degree.
Katie had two predictions about how deer might respond to the hunting season. One – they could shift their home range to a different location, as illustrated below (the brown track represents its home range prior to the hunting season and the blue is the result of hunting activity).
Or two – they could contract their home range. That is, only use a portion of their home range like this.
To assess whether deer shift or contract their home range (or don’t!) she used a relatively new tool in ecology called Hidden Markov Models, or HMMs. The models are named after Russian mathematician Andrey Andreyevich Markov (1856–1922) who studied stochastic processes and what is now known as a Markov chain.