Contrary to popular belief, Emperor Penguins do not mate for life. They are serially monogamous, only having 1 mate per year, but between years fidelity is at around 15%.

I think this means that they only choose last years partner 15% of the time. Still higher than random chance, but in no way dependant on their partner.

Was looking up something else on Wikipedia and stumbled onto this fact. I know this is not exactly related to the point you wanted to make, but I might as well share it.