The Dog and the Sparrow is a children's fairy tale by the Brothers Grimm, and a classic. 
A dog owner lets his shepherd dog starve from hunger, causing the dog to leave home. The dog meets a sparrow and accompanies him to the city. The bird captures meat and bread for the dog as a sign of gratitude. When they leave town night falls and they decide to go to sleep. During the night the dog is run over by a man in a horse carriage. The sparrow alerts the man on the carriage, but he ignores the sparrow and runs over the dog. She curses the man by announcing that he will turn into a poor man. Then she pecks the wine barrels the man was transporting open, so that the precious wine leaks out. The bird also pecks out the horses' eyes. When the man tries to kill the bird with an axe he accidentally slays his own horses down. As a result the man is forced to leave his now useless carriage behind and returns home.