After a time he noticed some swallows circling about over the grass near him. They were very small and did not look like the swallows that he had seen back east, most of which have breasts about the colour of iron rust. These little fellows were wonderfully quick, so much so that sometimes it was hard for the eye to follow them. They made wide circles out over the grass, or again flew so close to the house that it seemed as if they must dash themselves against the logs. Suddenly, one of them flew squarely toward the house, but when he had almost reached it, turned upward and alighted on one of the roof poles, where he sat, twittering faintly, and occasionally arranging his feathers. Sometimes the little bird walked a few inches, turning himself this way and that, and then Jack could see that his back was almost the colour of a peacock's tail, shining green in some places, and shining purple in others. He felt sure that he could describe this bird well enough so that his uncle could tell him what it was. All at once, to his surprise, the swallow walked into a hole between two of the roof poles, and was not seen again, but a moment afterward another little bird, just like the first, except that its back was dull brown, walked out of the hole and flew away over the valley. Jack did not know very much about birds, but he decided that this last one was the female, and that these two little swallows had a nest somewhere in the roof. He determined too that he would watch them and see what they did every day, for they were so pretty and so quick and graceful that it was fun to look at them. About noon he saw his uncle and Hugh ride up to the barn and unsaddle, and before long he was asking about the swallows. "Why yes," said his uncle, "those birds build there every year. They are a pair of violet green swallows; there are lots of them here in the mountains, and they build in little holes in the dead trees, or in the rocks; but these two have a nest somewhere up in the roof, every summer. I think it was last year that the young ones, when they were about full-grown, flew out of the nest and fell into the muslin that forms the ceiling of the sitting-room. They scrambled around there for nearly a whole day, and made so much noise that finally we cut a hole in the muslin and got them out. They were about as big as the old ones, and full feathered, and the next morning we took them out and put them on the roof, and the old ones at once fed them and began to teach them to fly. If you want to find out what birds there are about here, you had better take my bird book down from the shelf and study it a little each day. I can help you, for I know the names of most of the common birds." Saying this, his uncle went into the house. "How are the calves, Hugh?" said Jack. "Have the coyotes been bothering them at all?"