u/Boundless-_-Void

As you know the example of brood parasitism of cuckoo and crow. I mean yeah, even if the cuckoo did lay on the crow's nest. How did cuckoo know to push the crow eggs. Like even if they got switched before birth, how can the egg know of it. So it should consider the crow's egg as a sibling rather than an opponent for food. Or is it that cuckoo were rather an cruel being from start??