Country diary: sweet smells along the Steel City riverbank

Sheffield, South Yorkshire: Conservationists are using hidden cameras, DNA testing and a sense of smell, to follow the lives of the city's otter population

A dank winter's day in the Steel City did not hold obvious promise of the transformative power of nature. But not far from where a gaggle of office workers were enjoying a fag break, a friendly conservation volunteer called Paul ushered me down a ladder to an otherwise inaccessible spot on the banks of the river Don. I found myself, like Alice down the rabbit-hole, in a new sort of country, a lush carpet of floating weeds and a swift-moving ribbon of clear water at my feet muffling the sound of traffic and freshening the air.

Paul and his colleague Karon were checking hidden cameras for a lottery-funded survey of Sheffield's small otter population, called Otterly Amazing! The motion-sensitive cameras have captured these shy creatures, hunting successfully in a river so polluted when I was a boy in the 1970s that it would literally catch fire.