Getting to places like Bangkok or Singapore was a hell of a sweat. But when you got there it was the back of beyond. It was just a series of small tin sheds.

Human beings, because we're so clever, have removed every single one of those population limiting factors... So nothing controls our increase in numbers except our own wish. Since I first started making television programs, the population of the world has increased three times. That's an extraordinary notion. Can it increase four times? Can it increase five times? The Earth is a finite size. So a point will eventually come when we run out of food, when we run out of space and when we will have destroyed most of the natural world. So ought we to do something about it before that happens?

I'm swanning round the world looking at the most fabulously interesting things. Such good fortune.

If I can make programmes when I'm 95, that would be fine. But I would think I'll have had enough by then.

Birds were flying from continent to continent long before we were. They reached the coldest place on Earth, Antarctica, long before we did. They can survive in the hottest of deserts. Some can remain on the wing for years at a time. They can girdle the globe. Now, we have taken over the earth and the sea and the sky, but with skill and care and knowledge, we can ensure that there is still a place on Earth for birds in all their beauty and variety - if we want to... And surely, we should.

What humans do over the next 50 years will determine the fate of all life on the planet.

If you watch animals objectively for any length of time, you're driven to the conclusion that their main aim in life is to pass on their genes to the next generation.