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LETTER XIV.

THE division of the feathered creation into land and water birds is very convenient, though by no means so correct as at first sight, or on a superficial observation, it might appear. Many of the birds mentioned in my last letter are in every respect so decidedly aquatic, that there can be no doubt on the subject; but, on the other hand, there is a considerable number of species which want what we might consider the characteristic marks of water-birds, and yet are almost entirely aquatic in their habits. The water-hen has already been mentioned, which, though not web-footed, can both dive and swim. The oyster-catcher, also, can do both, if necessity require; and, according to the observation of the accurate Montagu, the curlew can swim, and the sandpiper both swim and dive. The water-ouzel, again, which inhabits the stones and banks of mountain-streams, though not web-footed, can pursue its prey under water;

also dives frequently in pursuit of the smaller fishes. The osprey, or sea-eagle, lives chiefly on fishes, which it takes by pouncing on them as they come near the surface of the sea or lake; but it does not seize them, like the kingfisher, with the beak, but with its foot, and for this purpose the latter is finely adapted. Like the other eagles, it has one back and three front toes; but there is this difference in the foot of the osprey-its outer toe is larger than the inner -whereas, in other eagles, the inner is larger than the outer. Now, you will not at once see what great advantage can result from this; but there is something farther: the outer toe, while it is larger, is also moveable, so that, at pleasure, the bird can turn it back, in which position the foot would seem to have two front and two back toes; and it must be obvious to you, that by this disposition it will be rendered much more fit for grasping its slippery prey, than it would be without such contrivance. Mr. Montagu gives the following account of the osprey's mode of fishing" As we were crossing the bridge over the river Avon, at Aveton Gifford, on the 9th of April, 1811, we observed an osprey hawking for fish; at least its attention was arrested, and, like the kestrel in search of mice, it became stationary, as if examining

what had attracted its attention. After a

descended to within surface of the water,

pause of some time, it about fifty yards of the and there continued hovering for another short interval, and then precipitated itself into the water with such great celerity as to be nearly immersed. In three or four seconds the bird rose without any apparent difficulty, and carried off a trout of moderate size, and, instead of alighting to regale upon its prey, it soared to a prodigious height, and did not descend within our view.”

The cuckoo has a similar power of turning the outer toe backwards or forwards, but I have met with no reason assigned for this peculiarity; - it may not be improbable, perhaps, that the cuckoo lays her egg on the ground, and then conveys it in her foot to the nest of its future foster-parent. There is a little bird called the nuthatch, found in woods in various parts of England, the foot of which is, comparatively, very large. The bird is about as big as a sparrow, yet, "when extended, the foot measures one inch and three quarters.' I know of no reason nor conjecture that has been assigned, to account for this great size; but I think that,

very probably, it is intended to enable the bird to pick up and carry nuts to the chinks in the bark of trees, in which it fixes them, till, by repeated pecking, the shells are split and the kernel picked out. Bewick observes, that, "when disturbed at its work, it very readily removes the nut and flies away with it," but I have no where seen it stated how it conveys the nut away.

When two toes are placed before, and two behind, the foot is called a climbing foot, the pes scansorius of ornithologists (see fig. 19.), but in it there is no voluntary motion of one

toe backwards or forwards at pleasure, as in the osprey and cuckoo. Many foreign species have this kind of foot; an example of which you may observe in the parrot. In Great Britain, I believe, it is confined to the wryneck and the woodpeckers. These birds live on insects; and the woodpeckers bore into the tree itself, whereever it is unsound, in order to come at the insects with which such parts are peopled. The legs are short and strong; and, by the disposition of the toes, the woodpecker can cling to the nearly perpendicular trunk of a tree for hours; which it could not do so well with any other than the climbing feet. The adaptation of the woodpecker to the mode of life it is destined to follow has been often adverted to by authors; and, indeed, it affords a very striking example of the perfection in which all is created: let us, therefore, enquire a little farther into it. We see that the climbing foot enables the bird to rest on the trunks or larger branches of trees, better than one of any other construction; but no matter how it may be formed, we can readily conceive that the muscles of a leg of any kind will at length tire by exertion. The claws of the woodpecker are strong and much hooked, and this gives additional facility of adhering to the tree. Still, however, the legs