Costumbres del cuclillo en el párrafo cuadrigentésimo décimo sexto de El Origen de las Especies

De interés para ornitólogos, este párrafo nada aporta en relación con la formación ni con la transformación de especies .   416   It has been objected that I have not noticed other related instincts and adaptations of structure in the cuckoo, which are spoken of as necessarily co-ordinated. But in all cases, speculation on an instinct known to us only in a single species, is useless, for we have hitherto had no facts to guide us. Until recently the…