The bird of Athena, the Greek goddess of practical reason, is the little owl (Athene noctua). Owls became symbolic of intelligence because it was thought that they presaged events. On the other hand, because of their nocturnal existence and ominous hooting sounds, owls have also been symbols associated with the occult and the otherworldly. Their secretive habits, quiet flight, and haunting calls have made them the objects of superstition and even fear in many parts of the world. In the Middle Ages the little owl was used as a symbol of the “darkness” before the coming of Christ; by further extension it was used to symbolize a nonbeliever who dwells in this darkness. Similarly the barn owl (Tyto alba) was looked upon as a bird of ill omen, and it subsequently became a symbol of disgrace. Scientific study of owls is difficult owing to their silent nighttime activity, with the result that the ecology, behaviour, and taxonomy of many species remain poorly understood.