[Rosie] The quantity of species that became extinct long before intelligent bipeds trod this earth is simply staggering. I think our impact is over-rated and, unless we don't believe in evolution, we should stop saving species that obviously don't have the necessary means to survive on their own. Also, I wholeheartedly agree with you on the matter of the naïve townsfolk who put food out for the most wiley of scavengers, so that the cute little feckers don't have to go and find food for themselves. I wouldn't mind getting rid of a few robins at the moment - either that or persuade them somehow to shut the hell up at night.
They switched to singing at night because modern noise pollution is so bad during the day that they can't hear themselves chirrup. If you want to Do Something about that, you'll probably have to join the Black Ops Arm of the Noise Abatement Society.
I was aware that rats were growing immune to many poisons, but this is the first I've heard about them needing a blood thinner to survive. Which begs the question: If warfarin is now an essential dietary additive for healthy rats, why don't we simply stop giving it to them?
(S M) I think the story is true though there's a possibility it may be a scientific urban myth. Without Warfarin the rats presumably will rapidly evolve back to what they were before the introduction of this substance although a number will perish in the process. Something more subtle is needed.