Question

I've got a small aviary at home with several different species ofbirds in it, and every so often when I have to add another onethere, because of natural losses, the different birds always seemto know what they are, the budgies don't try and mate with thecanaries and the finches don't try and shack up with the canaries.I was wondering how they actually knew what they were, and Iassumed it was just how they were brought up by the parents. Itthen did occur to me that how on earth do cuckoos manage? Cuckoos,being brought up by a foster parent of a totally different species,eventually grow up and spend a life as a cuckoo, behaving like acuckoo and finding another cuckoo to mate with.