When they go to sleep toucans double their tails over upon their backs, just as though they had hinges at the base, and bury their great beaks among the feathers of their shoulders. The consequence is that they do not look like toucans at all, or even like birds, and seem to be mere bundles of loose feathers. HORNBILLS These are more extraordinary still, some of them having beaks so enormous that they look as if they had been meant for birds twelve times instead of only six times as big as themselves. And the strangest thing of all is that upon the upper part is a great horny helmet, which in some cases is quite as large as the beak itself. In the rhinoceros-hornbill, indeed, the beak and helmet together are pretty nearly as big as the body. Both beak and helmet, however, except in one species, are made just like the bills of the toucans, so that in spite of their enormous size they are not at all heavy. But _why_ they should be so big is more than we can tell you. Hornbills are found in many parts of both Africa and Asia, and most of them live in the trees. They nearly always hop from one branch to another until they reach the very topmost boughs, where they will sit for hours together, occasionally uttering a series of loud, roaring cries, which can be heard for a very long distance. And when they fly they keep opening and closing their beaks, and so making an odd clattering noise which generally puzzles travelers very much when they hear it for the first time. There are two kinds of hornbills which live on the ground. One of these is found in South Africa, and the Kafirs have a curious idea about it, due to the fact that after death its body smells very nasty. They think that if one of these birds is killed and thrown into a river it will make the stream feel ill, and that a heavy fall of rain will take place in order that the carcass may be washed into the sea! So in times of drought they always try to kill a ground-hornbill and fling it into the nearest river. When one of these birds discovers a snake, its cries bring others to the place, and then, it is said, three or four attack the snake and kill it. Their plan is to advance upon it sideways with their wings spread out, and to irritate it with the tips of the feathers until it strikes. Then they all peck it together before it can recover itself, and nearly always succeed in killing it in a very short time. THE HOOPOE This is another odd-looking bird; but instead of having a horny helmet like the hornbills, it has a crest of very long feathers. These feathers, which can be raised or lowered at will, are tawny brown in color, with black tips, just before which is a streak of white. The body is grayish brown above and nearly white below, and the wings and tail are black, barred with white.