It lays only one egg and does not hatch it itself, but the mother bird in whose nest it has deposited it hatches and rears it; and, as they say, this mother bird, when the young cuckoo has grown big, thrusts her own brood out of the nest and lets them perish; others say that this mother bird kills her own brood and gives them to the alien to devour, despising her own young owing to the beauty of the cuckoo.