Natural history is not about producing fables.

[W]hen we look at the graphs of rising ocean temperatures, rising carbon dioxide in the atmosphere and so on, we know that they are climbing far more steeply than can be accounted for by the natural oscillation of the weather ... What people (must) do is to change their behavior and their attitudes ... If we do care about our grandchildren then we have to do something, and we have to demand that our governments do something.

I don't like rats, but there's not much else I don't like. The problem with rats is they have no fear of human beings, they're loaded with foul diseases, they would run the place given half the chance, and I've had them leap out of a lavatory while I've been sitting on it.

Do we really require so many gardening programmes, makeover programmes or celebrity chefs?

Birds are the most popular group in the animal kingdom. We feed them and tame them and think we know them. And yet they inhabit a world which is really rather mysterious.

I'm not a propagandist, I'm not a polemicist; my primary interest is just looking at and trying to understand how animals work.

The most extraordinary thing about trying to piece together the missing links in the evolutionary story is that when you do find a missing link and put it in the story, you suddenly need all these other missing links to connect to the new discovery. The gaps and questions actually increase - it's extraordinary.