Peter became very clever at helping the birds to build their nests; soon he could build better than a wood-pigeon, and nearly as well as a blackbird, though never did he satisfy the finches, and he made nice little water-troughs near the nests and dug up worms for the young ones with his fingers. He also became very learned in bird-lore, and knew an east wind from a west wind by its smell, and he could see the grass growing and hear the insects walking about inside the tree-trunks.