together, and the birds high up, I could not observe the manner of it—the sound (as I said before) being very peculiar. I therefore climbed the tree (which was easy), and the birds being now often quite near—though the branches and great clusters of needle-tufts were much in the way—I ascertained that it was the greenfinch alone which was producing the peculiar, vibratory noise, but how, exactly, he did it I could not make out. He appeared to be tearing at the woody sheaths or clubs (which stood wide apart) of the large fir-cones, and it seemed as though, to give the vibration in the sound, either the mandibles must work against each other with extraordinary swiftness, or the clubs of the cone itself vibrate in some manner against the beak, thus causing the sound in question to mingle with the scratching made by the latter against the hard surface.
"The great-tit and the nut-hatch are also busy at the cones. The former strikes them repeatedly with his bill, making a quick 'rat-tat-tat.' He attacks them either from the branch or twigs from which they hang, striking downwards, or clinging to the side of one and striking sideway-downwards, or even hanging at their tips, in which case he hammers up at them. Whilst hammering, or rather pick-axeing, he often bends his head very sharply from the body—almost at a right angle—towards the point at which his blow is aimed, and he then becomes, as it were, a natural, live pick-axe, of which his body is the handle and his head and beak the pick. After hammering a little on one of two cones that hang together, he perches on the other one, and, in the intervals of hammering it, shifts his head to the first and gives it, as
