The Borders is braced for a once-in-a-decade influx of Painted Ladies, with the potential for millions of the butterflies to wing in from southern Europe.
It’s all part of the longest known butterfly migration in the world.
Unusually high numbers of the orange and black butterflies have been reported amassing in southern Europe at the critical time of the year for them to spread northwards into Britain.
The butterfly is a common immigrant that migrates in varying numbers from the continent to the UK each summer, where its caterpillars feed on thistles.
But around once every 10 years, the UK experiences a Painted Lady ‘summer’ when millions of the butterflies arrive en masse.
The last mass immigration took place in 2009, when around 11 million Painted Ladies descended widely across the UK, with the butterflies spreading into the most northerly parts of Scotland.
Since then, the UK has experienced five years with below average numbers, but scientists are hopeful that 2015 could be very different.
Painted Ladies are experiencing their best year on the continent since 2009.
The offspring of these butterflies could be UK bound imminently.
The organisation Butterfly Conservation reported that some butterflies arrived during mid-May, but a spell of poor weather temporarily halted the immigration.
Recent warm, sunny conditions have seen Painted Lady numbers soar once again with reports of large numbers of the butterflies seen at south coast sites – suggesting a large-scale immigration may once again be about to take place.
Barry Prater, of Butterfly Conservation East Scotland, said: “Back in 2009, plenty Painted Ladies were seen across Scotland and we recorded some high numbers in the Borders. It’s a butterfly which is regularly seen feeding on garden flowers, particularly buddleia bushes, so people should be able to spot some over the coming two or three months if we get a good quantity coming over.
“This will tie in nicely with the annual Big Butterfly Count which Butterfly Conservation organises – this year it takes place over the three weeks from July 17 to August 9, and all people need to do to take part is find a spot to see some butterflies (which could be their garden, a local park or somewhere outdoors that they visit) and count all they see for just 15 minutes.
“Sightings of the Painted Lady form part of Butterfly Conservation’s ‘Migrant Watch’ and should be sent in to Butterfly Conservation where an on-line map shows the current situation. It has already been spotted in Dumfries & Galloway and Northumberland, so should be here soon.”
Richard Fox, Butterfly Conservation’s head of recording, explained: “The Painted Lady migration is one of the real wonders of the natural world.
“Travelling up to 1km in the sky and at speeds of up to 30 miles-per-hour these small fragile-seeming creatures migrate hundreds of miles to reach our shores each year, even though none of the individual butterflies has ever made the trip before.”
The Painted Lady undertakes a phenomenal 9,000-mile round trip from tropical Africa to the Arctic Circle each year – almost double the length of the famous migrations of the Monarch butterfly in North America.
Research using citizen science sightings from the 2009 migration revealed that the whole journey is not undertaken by individual butterflies, but in a series of steps by up to six successive generations.
Painted Lady sightings can be recorded via Butterfly Conservation’s Migrant Watch scheme.
More details, including an identification chart, are available on the Butterfly Conservation website www.bigbutterflycount.org