The speckled wood has expanded its range and population massively as a result of the warming climate.
The butterfly has experienced a 71 per cent increase in distribution and a 84 per cent increase in abundance in the last 40 years.
This increase comes at a time when more than three quarters of UK species are in a state of decline with many widespread butterflies also experiencing worrying slumps.
As the UK’s climate has warmed the speckled wood has spread to colonise East Anglia, the Midlands and much of northern England.
The butterfly has also become much more widespread in Scotland where in the 1970s it was restricted to the mildest areas on the west coast and the Moray Firth.
“As well as being a welcome new addition to woodlands and gardens in many parts of the UK, the butterfly provides a fantastic opportunity to study the impact of climate change on our native species,” said Butterfly Conservation’s Richard Fox.
The species flies in partially shaded woodland with dappled sunlight.
As part of this year’s Big Butterfly Count, Butterfly Conservation and the Tree Charter are asking the public to look out for and record the speckled wood.