Children have lost touch with the natural world and are unable to identify common animals and plants, according to a survey.

Half of youngsters aged nine to 11 were unable to identify a daddy-long-legs, oak tree, blue tit or bluebell, in the poll by BBC Wildlife Magazine. The study also found that playing in the countryside was children's least popular way of spending their spare time, and that they would rather see friends or play on their computer than go for a walk or play outdoors.

Sir David Attenborough warned that children who lack any understanding of the natural world would not grow into adults who cared about the environment. "The wild world is becoming so remote to children that they miss out," he said, "and an interest in the natural world doesn't grow as it should. Nobody is going protect the natural world unless they understand it."

Fergus Collins, of BBC Wildlife Magazine, said the results "reinforce the idea that many children don't spend enough time playing in the green outdoors and enjoying wildlife "something older generations might have taken for granted".

Experts blamed the widening gulf between children and nature on over-protective parents and the hostility to children among some conservationists, who fear that they will damage the environment. They said that this lack of exposure to outdoor play in natural environments was vital for children's social and emotional development.