Common Blue (male/upperwing) - Peter Withers

A beautiful blue butterfly which has been struggling for the last 40 years could be making a comeback in Northern Ireland, wildlife charity Butterfly Conservation can reveal.

The Common Blue is the most widespread of the UK’s blue butterflies and during the record-breaking hot weather in 2018, Common Blue numbers soared across Northern Ireland, increasing by 75% on the previous summer.

Now, with the UK experiencing another heatwave and the Met Office forecasting continued warm weather for Northern Ireland throughout August, experts are predicting the Common Blue could see its best ever summer.

Butterfly Conservation is also keen to see if 2019 really has been a Painted Lady summer – a once in a decade butterfly phenomenon when millions of the butterflies arrive en masse from Europe and Africa.

People across the UK counted more than 30,000 in just two days last week and great clouds of Painted Lady butterflies have been seen all over Northern Ireland since then.

Painted Lady (upperwing) - Iain Leach
A Painted Lady Butterfly

People are being asked to look for the Common Blue and Painted Lady and record their sightings as part of the Big Butterfly Count – the largest survey of its kind in the world.

The Common Blue is not typically found in gardens, preferring unimproved grassland such as downland, woodland clearings, heathland and even sand dunes.

Common Blue (female/upperwing) - Iain Leach
A female Common Blue

Butterfly Conservation’s Senior Surveys Officer, Dr Zoe Randle, said:

“People should be able to spot these butterflies in many places, especially where the wildflower Common Bird’s-foot-trefoil is found, as this is the main foodplant for their caterpillars.

“The Common Blue did exceptionally well in Northern Ireland last year and the country has experienced a really good summer so far, which is great news for this butterfly.

“The forecast for August is saying to expect more showers, but in between any rain, we’ll have sunny spells and crucially temperatures will remain warm in Northern Ireland, so we need people to get outside and take part in the Big Butterfly Count whenever they can.

“We’ve already had some Common Blue sightings reported in Northern Ireland this week, so we’re keen to track its progress and see if this butterfly’s fortunes really have turned around, or whether the Common Blue still needs our help.

“We’re also keen for people to keep recording any Painted Lady sightings, as this could be a record year for them, so keep counting and we’ll reveal the total number after the 11 August!”

Common Blue males have unmarked, bright blue upperwings, but females have orange crescents and dark spots near the outer edges on a ground colour that varies from purple-blue to dark brown, with a mere tinge of blue near to the body.

The underwings of both sexes have numerous black spots, with white halos and orange marks around the edges.

Common Blue [m], Occombe Farm, 23.7.19 (Dave Holloway)
A male Common Blue, by Dave Holloway

People can do a Big Butterfly Count anywhere, but Butterfly Conservation Northern Ireland are also inviting people to join them on a trip south into the Republic of Ireland for the final weekend of the survey.

A guided butterfly walk and Big Butterfly Count is taking place at The Burren in County Clare on Saturday 10 and Sunday 11 August.

More details on this can be found at:

The Big Butterfly Count, sponsored by B&Q, runs until Sunday 11 August. Taking part in the Count is easy - find a sunny place and spend just 15 minutes counting every butterfly seen and then submit sightings online at