Ellie Harrison takes to London's crowded streets to find out how our urban wildlife copes with living alongside millions of people. She visits the most urban woodland in London - a disused Victorian cemetery that is a haven for people and wildlife; and the London Wetland Centre, an oasis in the heart of the capital where wildlife is thriving.Ben Fogle visits 'Hedgehog Street' in Bristol, where residents have joined together to make their gardens hedgehog friendly; bug hunter George McGavin tracks down our largest and most fearsome insect, the mighty stag-beetle; and David Lindo tramps the streets of the capital in a quest to see our most rapidly declining bird - the humble house sparrow. Finally, Ellie marvels at the peregrine falcon which has recently colonised city centres up and down the country - and gets to ring one of the precious chicks nesting on Norwich Cathedral.