"Why, boys, some have supposed that it was for the male bird to sit on and keep watch, while the female was inside of the nest sitting on the eggs; but I think this is a mistake. And some have said, that when the female leaves the nest, and the male wishes to go too, he sits in this pocket, and beats against the side of the nest with his wing until he has made the edges of the top meet, and thus shuts up the mouth of the nest, and keeps off insects and other animals that would eat the young ones; but I do not believe this story." "Then what do you think the pocket is for. Uncle Philip?" "I think, boys, that it is nothing but a perch, or place for the bird to sit on before going into the nest. If the bird had no such place for stopping, it might be troubled to get into its nest. The mouth is small, and the bird could not enter it with its wings spread; and if it should alight on the edge of the nest constantly, it would injure it, for it is but slightly made. And I will tell you another reason why I think this is the use of the pocket. There is another bird in South Africa, called the pinc-pinc, which is the same species of bird as the Cape-tit; and this bird we know uses its little nest built upon the side of the other merely as a resting-place before going into the nest." "Uncle Philip, does the pinc-pinc build its nest like a bottle, as the Cape-tit does?" "No, boys, not so smooth, but felted in the same way. The nest is made mostly of the down of plants, and is either snowy white or brownish, according to the colour of the down. On the outside it is a clumsy-looking thing, but fastened, like the nest of the chaffinch, very firmly to the branches near it, so that you cannot take it away without breaking it to pieces. But rough as the outside is, you would be astonished, if you were to look at the inside, and see how a bird, and a small one too, with nothing but its wings, and tail, and feet, and bill for tools, could ever have worked the down of plants together, so as to make of it a piece of fine cloth. It has a narrow neck, something like a chimney, at the top of it. This is the entrance; and at the lower end of it there is a lump, which appears something like a small nest stuck on to the larger one; sometimes there will be three or four of these small-looking nests, and sometimes when there is a branch near the mouth of the nest which makes a good resting-place, there will be none. Here is a picture, boys, of the outside of one of these nests. [Illustration: Nest of the Pinc-pinc.]