[javman]

Population tanked around 1900 due to no regulations and massive human population moving west and everyone shooting deer on the way.

Conservation movements (mostly by sportsmen AKA hunters) led to regulations (each state now has a wildlife or game department to set hunting seasons) and a shift away from harvesting anything to mostly just harvesting bucks during short seasons.

Recent downward trend is due to several things:

1. Loss of habitat due to humans. Mule deer are known to migrate hundreds of miles, and there are a lot of highways to cross. Winter habitat is being paved over for human progress. (Cool video here: https://www.youtube.com/watch?v=BIAyb-1uwTg)

2. Chronic wasting disease is an issue in wild mule deer populations with no cure (similar to mad cow disease)

3. Harsh winters can take a toll and really slow any chance of mule deer population growth. Certain places in Wyoming this year had 100% fawn mortality (every deer less than a year old died due to the harsh winter, see: https://www.wyomingnews.com/rocketminer/news/state/what-s-in...).

4. The internet has enabled a lot of out-of-state hunting, by making it easier to find places to hunt (Google Earth, OnX, etc.), learn how to hunt better, and understand the regulations, so there are more hunters on the landscape with better technology. States manage for this and limit the number of hunters and shorten seasons.

5. Predator re-introduction/recovery as well as many states that have banned certain types of predator hunting. This can be a touchy subject among hunters. A lot of people are okay with deer and elk being hunted but not wolves, cougars or bears.

I've been deer hunting for 30 years. My experience is with mule deer and black-tailed deer on the west coast and Rockies. Not much whitetail experience, but I do know that whitetail deer in the east and south don't have as many predators and do well in agricultural landscapes. They can have two or three fawns each year so their population can grow quickly. Mule deer inhabit harsher landscapes (mountainous terrain mostly).

[mhardcastle]

Regarding (1), for blacktails I'd add meadow encroachment. Parts of their range have sees a sizeable portion of the meadows where they browse taken over by conifers and shrubs. These were kept in-check by fires pre-1500.

[crazygringo]

Thank you so much for all this info!