It is inferred that Birds possess some notion of power, and of cause and effect, from the various actions which they perform. "Thus," relates Dr. Fleming, "we have seen the Hooded Crow in Zetland, when feeding on small shell-fish, able to break some of the tenderer kinds by means of its bill, aided in some cases by beating them against a stone; but, as some of the larger shells, such as the buckie and the welk, cannot be broken by such means, the Crow employs another method, by which, in consequence of applying foreign power, it accomplishes its object. Seizing the shell with its claws, it mounts up into the air, and then loosing its hold, causes the shell to fall among stones (in preference to the sand, the water, or the soil on the ground), that it may be broken, and give easier access to the contained animal. Should the first attempt fail, a second or third is tried, with this difference, that the Crow rises higher in the air, in order to increase the power of the fall, and more effectually remove the barrier to the contained morsel. On such occasions we have seen a strong Bird remain an apparently inattentive spectator of the process of breaking the shell, but coming to the spot with astonishing keenness when the efforts of its neighbour had been successful, in order to share the spoil. Pennant mentions similar operations performed by Crows on mussels." The brain of Birds is, in general, large in proportion to the size of the body, and the instinctive powers are very perfect. A few kinds are rather dull and stupid; but the Parrot, Magpie, Raven, and many others, show great vivacity and quickness of intellect. The Raven has a great deal of humour in him. One, a most amusing and mischievous creature, would get into a well-stocked flower-garden, go to the beds where the gardener had sowed a great variety of seeds, with sticks put in the ground with labels, and then he would amuse himself with pulling up every stick, and laying them in heaps of ten or twelve on the path. This used to irritate the old gardener, who drove him away. The Raven knew that he ought not to do it, or he would not have done it. He would soon return to his mischief, and when the gardener again chased him (the old man could not run very fast), the Raven would just keep clear of the rake or the hoe in his hand, dancing before him, and singing as plainly as a Raven could. "Tol de rol de rol! tol de rol de rol!" with all kinds of mimicking gestures.