Of cuckoos and cowbirds

Everyone knows about the cuckoo and that it lays its eggs in other birds' nests. "The Economist" ( a regrettably subscription-only feature) last week reported on the cowbird, a bird that also lays its eggs in another 's nest.
But the evolutionary strategies are completely different.
The cuckoo disguises its egg by laying eggs of the same colour as the host eggs. The host doesn't recognise it - otherwise, it would throw it out. So it raises the egg as its own.
It's what evolutionists call an "arms race". The defensive strategy is for the host bird to recognise hostile eggs and thrown them out. The cuckoo's tactic is to develop eggs that look like the hosts.
But the cowbird is different. It lays the egg, then checks round regularly. If the egg it laid is missing, it wrecks the nest and tries to kill the other eggs and nestlings.
So the host bird goes along with it and raises the one egg as its own, in order to protect its own two or three eggs.
None of this is conscious, of course. It's all done by genetics and instinct. But it's as explicit a protection racket as you'll see in nature. "Look after my egg or I kill yours".

What was that about Gaia and benevolent Mother Nature again?