Warm-bloodedness is one of the key factors that have enabled mammals to conquer the Earth, and to develop the most complex bodies in the animal kingd… - David Attenborough

The island is immense. It's 1,000 miles long, if you discount a narrow arm of sea that crosses it in the middle, and it contains mountains over 12,000 feet high. It's New Zealand. The first land-living mammals to get here were human beings and they didn't arrive until a mere 1,500 years ago. So here you can glimpse what the world would have been like if the birds had won that battle with the early mammals and now ruled the Earth, for here they once did.

Each [pelican] has already survived many perils in its young life. As a chick, it fought battles with its brothers and sisters and won.

Midwinter, and the countryside is so still, it seems almost lifeless. But these trees and bushes and grasses around me are living organisms just like animals. And they have to face very much the same sort of problems as animals face throughout their lives if they're to survive. They have to fight one another, they have to compete for mates, they have to invade new territories. But the reason that we're seldom aware of these dramas is that plants of course live on a different time-scale.