Cuckoo (2015 - )
The adult cuckoo bird doesn't build a nest to lay it's eggs in, instead it will invade another birds nest. To prevent any suspicion the Cuckoo bird will remove a few of the other birds eggs and lay one of it's own in the nest. The Cuckoo bird is able to lay eggs that resemble the eggs laid by the mother bird. When the baby cuckoo hatches the adopted mother will begin feeding it just as it were her own. When the baby gets strong enough it will then try to roll the other eggs out of the nest. When it has completed it's task it will remain in the nest until it is fully grown.
I like the irony of the whole thing, for the mother to love her child she must leave it. For her to ensure the survival of her own she kills another.