Sources : Gracocenderon

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.53): The Gracocenderon is a bird of the East, which they say is endowed with wonderful chastity and temperance. Indeed, this bird, among all the living things of the earth, accomplishes its generation by the smallest copulation. For it gathers only once a year, and this for the glory of the children; and for this reason it is extirpated from all lust. Let him therefore be ashamed, who is capable of reason, who gathers indifferently at all times, and has no way of controlling it, but his weak body is exhausted by lust, and excessive luxury does not fear to hasten his days. - [Badke translation/paraphrase]