We bought this feeder several years ago because it was supposed to stop larger birds from raiding it.  As you can see our resident crow has no trouble getting a bite.  First he hangs by one talon and gets his beak in the sunflower seeds.  Best of all for him is he knocks a bunch on the ground.  Then he just leisurely feeds on that along with the small birds and squirrels.

Smart to say the least!!