Flying high: why peregrine falcons are kings of the urban jungle

Last century, the cliff-dwelling bird of prey almost became extinct in Britain. Now it has reinvented itself as a city creature. What is behind this spectacular recovery?

By the four chimneys of Battersea power station, between tower cranes and builders' cabins, is an unobtrusive metal mast. At the top, a watchful figure looks down upon the 3,000 workers bustling around this vast 9bn construction site.

"Female," says David Morrison, with a deft glance through his binoculars. "She's protecting her nest site. There was an intruding female about half an hour ago."