As might be expected for a recently discovered bird species in the continental United States—only the second in nearly 80 years—the Cassia Crossbill (Loxia sinesciuris) is range-restricted. It occurs in just two small mountain ranges on the northeast edge of the Great Basin Desert where it is engaged in a coevolutionary arms race with lodgepole pine. Based on a current paper in The Condor: Ornithological Applications, Cassia Crossbills occupy about 70 km2 of lodgepole pine forest and number only ~5,800 birds.