At the turn of the century, America’s wild bison — which at one time numbered 60 million — had dwindled to about two dozen animals. Strong, sturdy and resilient, they’ve made a comeback, thanks to public and private conservation efforts. On the range, in refuges and national parks, this symbol of our wildlife heritage is magnificent to observe. Here are five places where you can snap a shot of this American icon — with a zoom lens: 1. Custer State Park, S.