Increase in migration of Large Tortoiseshell butterfly into the county

There has been an increase in the migration of Large Tortoiseshell butterflies into the eastern counties of the UK with 11 sightings made so far in areas across the breadth of Suffolk and Norfolk.

While the odd individual slipping across the channel in high summer is not unusual, Butterfly Conservation volunteers have received more reports this month than in the whole of the previous 10 years.

Not to be confused with the Small Tortoiseshell butterfly, a very common household species which frequents gardens across the UK during the summer months, the Large Tortoiseshell is an immigrant species.

Kiri Stuart-Clarke, volunteer for Butterfly Conservation’s Norfolk Branch says: “This is an incredibly exciting discovery for 2020 and we can’t wait to see how many further sightings are recorded over the coming months. We don’t yet know the reasons for the re-emergence of the Large Tortoiseshell into the UK but the more data we have the better.

“We’re asking the public to help us by recording any sightings they make. The weather and wind direction has been favourable for immigration so they could pop up just about anywhere. If you are lucky enough to spot a Large Tortoiseshell either in your own garden or while on your daily exercise you can record your sightings and contribute to our data. Go to Butterfly-conservation.org/mysightings to download the iRecord app. And don’t forget to share a picture of your sighting too.

“It’s important to provide a positive identification when submitting a recording as it could be easy to mis-identify the butterfly as a Small Tortoiseshell or Comma. The native Small Tortoiseshell is obviously much smaller, while the Large Tortoiseshell also has distinguishing features including uneven forewing bars, an extra black forewing spot and is a paler orange in colour.

‘We know that it’s highly likely that people might spot these species in their gardens over the coming weeks. Other European countries such as Holland are seeing the best emergence of this species for 40 years.”

Ian Griffin, a butterfly enthusiast, said: “I was on a local walk as part of my daily exercise and came across a Large Tortoiseshell butterfly in a churchyard in Melton Constable. Luckily, I had my camera with me and was able to take a picture. I didn’t realise it was such a special butterfly to spot until I looked back at the pictures the following morning and could make a positive identification. What an exciting find.”

Anyone can be a citizen scientist and record the butterflies that they see in their garden, outdoor space or on their daily exercise. All further data that can be captured about the Large Tortoiseshell, it’s whereabouts and population numbers, over the coming weeks is vital towards tracking and ultimately understanding its arrival of this species into the UK.