The only acceptable way to solve ecological problems is if you can persuade people to have fewer children. In the Victorian times, there were families of 15 children. Someone like Edward Lear, he was the last of 21 children. And so what we have to think about is offering people the alternative choice. And in the West, that's what's happening. The birth rate has been dropping steadily and still is. I'm wanting human beings to be better off so they don't view children as an insurance for the future.

What I am interested in with birds, just as I am with spiders or monkeys, is what they do and why they do it.

We really need to kick the carbon habit and stop making our energy from burning things. Climate change is also really important. You can wreck one rainforest then move, drain one area of resources and move onto another, but climate change is global.

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 remember when we were in the World Cup in Australia and I had to win the singles against Tony Payne, best of seven legs, to win it. I was 2-0 down but ended up beating him I suffer much less than many of my colleagues. I am perfectly able to go to Australia and film within three hours of arrival.

I just wish the world was twice as big and half of it was still unexplored.

I'd like to see the giant squid. Nobody has ever seen one. I could tell you people who have spent thousands and thousands of pounds trying to see giant squid. I mean, we know they exist because we have seen dead ones. But I have never seen a living one. Nor has anybody else.