Indeed, there seem to be only two tribes which have any use for wing-claws during nestling life. One of these is represented by the gallinules, that is to say, the coots, and water-hens, and their kind. You may test this whenever you have the good fortune to capture a young water-hen. Place him outside the nest, and especially if it happens to be a little raised, you will see him make his way back, using feet, wing-claws, and beak. His wings, it will be noticed, at this stage are used as fore-legs. The other tribe is represented by that strange bird the hoatzin of the Amazon. Here the two claws are really large, and they play a quite important part in his early life. For the young hoatzin is hatched in a nursery--a crude nest of sticks--placed on the boughs of a tree overhanging the water. As soon as hatched he begins to climb about the branches. Should he fall, by some mischance, into the water, he promptly swims to the bank; and by the aid of his long first finger, and wing-claws, and his huge feet, soon climbs back. But the most wonderful part of his story is yet to come. [Illustration: _Grouse_] So long as these youngsters can only scramble about they are in constant jeopardy. A wing-surface at least big enough to break the force of a fall is an urgent necessity. And so the growth of the quill-feathers is, so to speak, pushed forward with all possible speed. But if all the feathers grew at the same rate, there would speedily come a time when the outermost feathers would make the claw at the end of the finger useless, while the wing-surface, as a whole, would be insufficient. To obviate this difficulty, the development of the outermost feathers is held in abeyance till the inner feathers of the hand, and the outermost of the fore-arm, have grown big enough to suffice to break the force of the fall. As soon as this stage is arrived at, the outermost quills, whose growth has been held in abeyance, rapidly develop; the finger decreases in length, and its claw disappears, while that of the thumb soon follows suit. And thus it comes about that the hand, in the nestling, is relatively much longer than in the adult. But in its mid-period it may be taken to represent the adult stage of the wing of the ancient Archæopteryx. This bird could have been but a poor flier, and probably during the time it was moulting its quills it was absolutely flightless, so that it needed a permanent finger-tip, and claw, beyond the margin of its wing-surface.