But the swallows rarely fail to come in the spring, and soon begin to repair their nests or build new ones with mortar from the roads; a rainy day is very useful to them, and they alight at the edge of the puddles, finding the mud already mixed and tempered for them there. In such weather they will fly backwards and forwards by the side of a hedge for a length of time, skimming just above the grass, when, looking down on them instead of up at them, the white bar across the lower part of the body just before the tail forks is very noticeable. The darker feathers have a glossy bluish tinge on the black. They seem fond of flying round and near horses and cattle, as if insects were more numerous near animals. While driving on a sultry day I have watched a swallow follow the horse for a mile or more. It is a pleasant sight to watch them gliding just above the surface of smooth water, dipping every now and then. Once, while observing some swallows flying over a lake, on a windy day, when there were waves of some size, I saw a swallow struck by the crest of a wave and overwhelmed. It was about twenty yards from a lee shore, and the bird floated on the water, rising and sinking with the waves till they threw it on the bank. It was much exhausted, but when placed on a stone in the warm sunshine soon recovered and flew off. As another proof that quick as they are on the wing, they do not always judge their position or course precisely, I know a case where a swallow, in less than ten yards after leaving her nest under the eaves of a house, flew with great force against a door in the garden wall painted a dull blue. The beak was partly broken and the bird completely stunned: she died in a few minutes. There was some one in the garden close by at the time: his presence may have frightened the swallow; yet they are not usually timid where their nests are undisturbed. Perhaps in her hurry the dull blue colour of the gate may have deceived her sight; but she must have travelled that way a hundred times before.