A few springs ago I was visiting Denver and decided to make an overnight trip to Rocky Mountain National Park, through Estes Park. The higher passes and most scenic drives were closed because of snow and ice, but I was rewarded with a memorable display of wildlife, the quantity of animals reminding me of what one sees on safari in Africa. There were hundreds of elk in the park, extending into Estes Park beyond the park's boundary. The grass and vegetation at the lower elevations were exposed and herds of elk cows aggregated here enjoying the warming weather and access to grass.
I returned to Rocky Mountain NP during summer a year or so later and did not see a single elk during that visit. During the warm summer months the elk ascend to remote high mountain meadows. As with so many things in life, timing is everything!