Attenborough calls on public to count butterflies
13 July 2011 Last updated at 12:36 BST
Sir David Attenborough, who is president of Butterfly Conservation, has asked the public to spend 15 minutes counting butterflies.
Butterflies are seen as a key indicator of the health of the countryside and researchers want to find out how this year's hot, dry spring has affected their population.
Sir David told the BBC's Richard Westcott that all British butterflies are in decline.
Get involved in the butterfly count.