The Jamestown Sun  has a brief write up noting that North Dakota's mule deer population is again down continuing a four year trend. The article blames three years of harsh winters, but then notes that whitetail deer populations continue to increase. Perhaps whitetail encroachment in conjunction with harsh winters is driving the mule deer population down.
Three years of harsh winter conditions have increased adult mortality and reduced production. The last two years have resulted in the two lowest production rates ever documented, and biologists expect this year’s production to be similarly low. Conversely, white-tailed deer abundance in the badlands has increased during the last five years.