So a bit more about this. It's in response to this paper
Accelerated evolution of SARS-CoV-2 in free-ranging white-tailed deer - Nature Communications giving evidence that SARS-CoV-2 evolves faster in white tailed deer than in humans. This is relatively normal in an unexposed population, but the rate is unexpected.
The reason I asked the question is how the covid got into the deer in the first place, it's not like deer snogging is a regular event (I hope). The paper describe several human to deer events so I'm speculating this is related to hunting practices of baiting so that der congregate when they shouldn't or of "canned" hunting where deer are more closely managed. There was that video of a free ranging deer being darted to treat an abscess quite recently. SO I speculate that there are a few occasions when people are in close contact with white-tail who are then released and mingle with the larger population.
Thoughts please
PS - it's not thought to be a big problem, the changes that the mutations cause are not significant.