why are we humans so interested in how a bird can find its way home?birds brains function differently from ours.why do birds automatically know they have to sit on eggs till they hatch?how did itcome about that coocoos laid an egg in anither birds nest that is the same colour as those birds eggs.then all the chicks will hatch on the same day.the cooccoo chick then has to kick all the other siblings out the nest for its own survival.why does the sitters rear a youngster thats 3 times its size and is a different colour?