An endemic species — a plant or animal that lives in a single geographic area — is a gem of evolutionary biology. Idaho is home to a few (Bliss Rapids snails, anyone?), one of the most notable being the Cassia crossbill.
Crossbills are a group of six finch species that feature a curious-looking, overlapping crossed beak. The Cassia crossbill is also called Loxia sinesciuris, “loxia” meaning crosswise, and “sinesciuris” meaning “without squirrel.”
That’s because Cassia crossbills live in two neighboring mountain ranges: the South Hills and the Albion Mountains, where no red squirrels live. The Cassia crossbill’s distinctive beak is an evolutionary trait that allows them to pry open lodgepole pine cones and use their tongues to eat the seeds inside, which, because of the lack of squirrels to compete with, guarantees them an exclusive food source.
Most Cassia crossbill habitat is in Cassia County, to the right of the dotted line at the center of the map; Twin Falls is located just off the northwest corner of the map. (Idaho Fire Map)
However, ornithologists are worried about the small finch’s survivability in southern Idaho’s lodgepole pine forests. If you recall the fire season of 2020, you might remember that the Badger Fire raged across the South Hills for months, setting 90,000 acres of already scarce Cassia crossbill habitat ablaze.
For the past month, the Black Mountain Fire has been burning just a few miles west of the crossbill’s habitat, but it’s being monitored closely and allowed to burn to develop future habitat in the area.
The climate crisis is devastating lodgepole pines across the western U.S. and Canada, threatening an uncountable number of species, including this small songbird that can’t be found anywhere else in the world.
