Sources : Fatatore
Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.47): The fatatore is a bird inhabiting the region of the East. This bird, naturally desirous of procreating offspring, anticipates the season of spring, when, of course, other birds are wont to initiate conception. Hence it happens that which it hastens in the beginning, lacks blessing in the end. For the eggs which it lays before the spring season, when the cold still prevails, all perish during the winter and have no produce no offspring. But it has a remedy for this: for in the following hot season it lays eggs; and so the later eggs are completed and make chicks. This is in contrast to almost all wild birds, which come together once a year and lay eggs and brood. - [Badke translation/paraphrase]