Cassia Crossbill

Originally one of the ten subtypes of Red Crossbill, the type 9 subtype exclusively local to the South Hills of the Sawtooth National Forest in Cassia County in southern Idaho was split into a separate species in 2017. The Cassia Crossbill has a quite different vocalization, a larger bill, and unlike the nomadic habits of the other Red Crossbill subtypes, it remains local year round where, thanks to its bill size which has evolved specifically for this purpose, it alone can feed on the seeds found in the cones of the lodgepole pine.