The cuckoo does not manage her nursery affairs as other birds do. Most birds lay an egg a day, or every other day, so that they hatch about the same time; but this bird doesn't mind if several days come between. Thus it happens that one or more little cuckoos hatch out before the rest are ready, and it is common to find little ones of several ages in the same nest. There may be one nearly grown, another just beginning to get feathers, and a third one not yet out of the egg. There is another droll thing that may be found in a cuckoo's nest. When the feathers begin to grow out on young birds, they come wrapped in little sheaths. In most cases these sheaths burst open and the feathers show, when they are a little way out. But in this family it is different. The sheath does not open, says Mr. Dugmore, till the feathers have grown their full length. Till that happens, the youngster looks as if he were stuck all over with white pins on his black body. You have heard, or read, that the cuckoo lays eggs in other birds' nests, and leaves her young to be brought up by others. Do not forget that the bird who does that is the European cuckoo--not ours. Our cuckoos build nests, though very poor ones, sometimes hardly more than a platform of sticks. This bird is useful to us, for he eats some of our most troublesome insects,--such as tent caterpillars, which few birds like to eat because they are so hairy, and other insects with spines that are poisonous, and so generally avoided. The cuckoo is graceful in flight. He goes swiftly, without noise, and seems to glide through the thickest foliage with ease. I once found a young bird tumbling about on the ground. He was trying to fly, but was not able to go much more than a foot at a time. He was giving strange calls, which were answered from the woods beside the road by a low tapping sound. I thought of course the little one was a woodpecker and his mother was doing the knocking. It was so dark I could not see him well. After some trouble I caught him and was going to take a good look at him to see who he was before I let him go. As I grasped him he gave a shriek, and out from the thick trees popped a cuckoo. She alighted on a low branch outside and gave such a cry of distress that I knew at once it was her baby I held in my hand. I suppose the poor mother thought I wanted to carry the youngster off. I couldn't bear to have a bird think that for a minute; so I opened my hands and away he went, half flying, half scrambling up the road, while the mother slipped back into the woods. In a moment she began again her hollow-sounding calls, which I had thought were woodpecker tappings. FOOTNOTE: [25] See Appendix, 24. XXXII THE OWL FAMILY (_Bubonidæ_)[26] OWLS differ from all other birds in having eyes that look forward like ours. They have also a broad face, which is made to look even wider by the feathers which stand out around the eyes.