Despite a three-fold increase in the nation's magpie population over the last 30 years, only 29 percent of children were able to recognise the black and white bird, while half could not tell the difference between a bee and a wasp.

"It's a sad modern phenomenon that's left many of us, and in particular the younger generations, disconnected from the natural world," said TV naturalist Nick Baker as the NT launched a campaign to encourage families to spend more time outdoors.

"In an age where Nintendos and PlayStations compete with tree-climbing and pond-dipping, the virtual world is winning.

"With more kids better able to identify a fictitious alien than our national tree, the oak, something needs to be done.

As part of its campaign, the NT plans to tour England's major cities in a specially adapted red bus, complete with an outdoor garden on the top deck.

Starting in London on Tuesday, the "Bus to Space" will then visit Birmingham on July 9, Manchester and York on July 10 and Bristol on July 12.

The online poll interviewed 1,651 children, aged between 10 and 12, in June. (Reporting by John Joseph; Editing by Steve Addison)