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do u wanna know how a red crossbill's beak actually works? good because i'm gonna show you
so first they find a cone that's ready to pluck food out of - not so open that it's dropped all of its seeds, not too closed that they can't get to the food. then they slip the tip of their top beak in like the below:
then, they squeeze down, which pushes the scale of the cone outward, allowing them to access the seed inside. they grab the seed using their beak and tongue.
here's what the seed inside often looks like; it's winged, allowing it to glide on the way out of the cone. they use their tongue and bill to nibble away at any of the casing and covering, like the wing, just eating the edible part of the seed inside.
so, what benefit does the crossing actually have? well, there's a few: the skinny, curved points of the bill allow them to exert more force on the cone to separate the scale. also, the crossing promotes moving their mouth from side to side to add more prying force.
and yes, there are left-crossing and right-crossing crossbills - it's about 50-50. also, they typically have a dominant foot they use to hold the cone (though this is more prevalent on crossbills that feed on larger cones).
also, if you weren't satisfied with the crossing answer, here's a more technical explanation from Birds of the World:
basically, the crossbill's bill is nature's little crowbar and i love that for them. thanks for following along!
(also, i’ve seen them pry the cone open both ways, using the top bill as well as the bottom bill to open the scale - the key is that they use the cross and their bill movement to create lateral force to spread the scales)
