Britain's butterflies are disappearing because we are destroying the places where they live.
Around three quarters of Britain's butterfly species have dropped in numbers during the last 30 years, even though the weather has changed to suit them.
Butterflies like hot weather, and the change in the global climate should have helped them.
Farms replace their habitat
But the number of butterflies in Britain has fallen, mainly because farms have been built where wild meadows, ancient woodland and moors used to be.
These are the types of land where butterflies like to live and breed, but with the land disappearing, the butterflies have been dying out.
The study was carried out by wildlife charity Butterfly Conservation and three UK universities between 1995 and 1999.