Warm weather may make 2019 a boom year for butterflies, say experts

The common blue butterfly could be booming in the UK thanks to recent spells of hot weather, according to a conservation charity.

Experts are predicting that the July heatwave and Met Office forecasts for above-average temperatures in August might mean that the common blue has its “best ever summer”, Butterfly Conservation said.

The butterfly has been struggling for the last 40 years, according to the charity, but common blue populations increased by 104% in the summer of 2018 compared with the previous year, thanks to warm weather.

Last summer, overall butterfly numbers were up 110% on 2017 in England and 94% in Wales, according to the charity.

The top of the male common blue’s wings are bright blue and unmarked, whereas females have orange crescents and dark spots near the edge of their wings that vary from purple to dark brown, with a tinge of blue near to the body.

Dr Zoe Randle, Butterfly Conservation’s senior surveys officer, said: “People should be able to spot these butterflies in national park areas as their caterpillars mainly feed on the wildflower and common bird’s-foot trefoil.” It could also be a record year for the painted lady butterfly, which is covered in orange, brown and white markings, she added.

Butterfly Conservation is urging people to help monitor the common blue by taking part in the Big Butterfly Count population survey.

Randle added: “It would really help us if people could get outside and look for this butterfly, so we can see if its fortunes really have turned around or if the common blue still needs our help.”

Participants are asked to spend 15 minutes in the sun counting every butterfly they see before submitting their sightings online.

Corinne Pluchino, chief executive of the Campaign for National Parks, said: “This is a great opportunity to help chart the progress of this beautiful blue butterfly and we’d love to know where our top common blue colonies are.”

The Big Butterfly Count runs until 11 August.