Red Crossbills are a part of a small family of birds that have evolved extreme crossbites.
This looks like a beak deformation, but it is actually a highly evolved tool for obtaining a food source that many other birds can't access - pine nuts!
Pine cones (and also cones from other conifer species like fir and spruce) have large seeds tucked deep inside of them. We humans call these seeds 'pine nuts'... and we pay a premium for them!
For most birds, these seeds are packed far too deeply and tightly inside the cone for their beaks to get at them. Crossbills however, have both the tool and the technique:
After landing on conifer cone, a Red Crossbill opens its beak so the normally-crossed tips line up with each other. It inserts its beak in a crack between cone scales and then closes it, the now-crossed tips forcing the scale open with lever-like force. Turning its head, it forces the scale open even more, and its extendable tongue reaches in to grab the hidden seed at the bottom.
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