With many national parks across the country in trouble from such myriad threats as climate change, overcrowding, energy exploration, invasive species, and poor air quality, National Parks Traveler’s new “Threatened and Endangered Parks” lists, published today, identify parks that are struggling to retain the very essence that led to their inclusion in the National Park System in the first place. In this week's show, Phil Francis of the Coalition to Protect America's National Parks and Mark Wenzler from the National Parks Conservation Association discuss the threats facing the parks.

Kyle Joly, a National Park Service wildlife biologist who long has studied terrestrial migrations in national park units in Alaska, discusses the longest land migrations in this week's show. Caribou and reindeer at the top of the long-distance travelers, but what about wolves? Contributing writer Kim O’Connell, fresh back from a visit to New Orleans, gives us a preview of her time at Jean Lafitte National Historical Park and Preserve.

John Garder, the senior director of budget and appropriations for the National Parks Conservation Association, discusses congressional action on legislation to address the roughly $12 billion in backlogged maintenance needs across the National Park System. Becky Lomax, author of Moon USA National Parks, talks about what she's seeing in the parks in terms of that maintenance backlog, and we share thoughts about efforts to build a commercial spaceport just west of Cumberland Island National Seashore.

This week Doug Smith, who heads Yellowstone National Park’s Wolf Project, discusses how successful the wolf recovery program has been. We also visit with the executive director of the National Parks of Lake Superior Foundation to discuss the five national park units the foundation works with, and end with a look at fall and winter migrations across the National Park System.