Rick Wallen was the lead wildlife biologist for the bison program at Yellowstone National Park from 2002 to his retirement in 2018. He holds a Master of Science in Wildlife Management from Montana State University. Prior to his work in Yellowstone, Wallen worked in ungulate management programs at Grand Teton, Redwood and Bryce Canyon national parks. In this Q&A series, Rick answers a range of questions about the challenges of bison conservation and the park's management goals.