Clark’s Nutcracker and the whitebark pine have a strong mutualistic relationship: the tree is the bird’s best source of food, and the bird is the tree’s most dependable seed disperser. But several factors are putting the tree at risk — and the decline in whitebark pines is making that partnership less stable.Peri Sasnett, a ranger at Glacier National Park and co-host of the park’s podcast Headwaters, joins Tenijah to talk all about the birds, their intricately interconnected ecosystems, and ways researchers are learning if and how the birds are adapting. Season 2 of Glacier National Park's podcast Headwaters is all about the charismatic whitebark pine and its role as a keystone species.More info and transcript at BirdNote.org.Want more BirdNote? Subscribe to our weekly newsletter. Sign up for BirdNote+ to get ad-free listening and other perks. BirdNote is a nonprofit. Your tax-deductible gift makes these shows possible.