Most wildlife give birth in the spring, making this a great time of year for wildlife viewing. In areas like Lamar Valley and Hayden Valley, bison calves are seen scampering along with the herd. And in Mammoth, elk calves are learning to walk and explore. (It is important to remember to keep a good distance between yourself and a cow elk, as they are very protective of their calf.)
Another good time of the year to watch wildlife is in the fall. Mating, also called the rut, occurs this time of year; the bull elk, bull bison and big horn ram can be seen in certain areas strutting around, and defending their harem.
Lastly, winter is a fantastic time to view wildlife. Winter is a magical wonderland in Yellowstone, it is full of snowy forests, iced geysers, frozen waterfalls, and hanging icicles. The wildlife concentrates to lower elevation, so bison, elk, big horn sheep, wolves, foxes and coyotes are abundant in the valleys and can be viewed when skiing and showshoeing. An icicle-covered bison trudging through a snow-covered meadow is a marvelous sight.