LISTEN: Dr Zoe Randle explains how butterflies numbers have changed in Highland Perthshire
The Big Butterfly Count is running for its eleventh year now, only this year has seen the lowest number of butterflies logged on record.
The count totals 1.4 million butterflies across the UK between 2019 and 2020, although this year saw the highest number of sightings submitted by the British public.
Dr Zoë Randle, Senior Surveys Officer at Butterfly Conservation said: “Unfortunately, this summer has not seen an abundance of butterflies, across the UK. We do see peaks and troughs of butterfly numbers each year (last year, for example, we saw a huge influx of migrant Painted Lady butterflies), so the data from the Big Butterfly Count is an important snapshot which, along with our other monitoring schemes, helps our understanding of the rates of decline of butterflies and moths”.
However, various species of butterfly are now migrating their way from the southern parts of the UK into the heights of Highland Perthshire.
Dr Randle, who also co-authored The Atlas of Britain and Ireland’s Larger Moths, added: “In Highland Perthshire, you’re likely to find the usual suspects, Meadow Brown, Large Whites, Small Whites, Peacocks, Small Tortoise Shell, Speckled Wood.”
According to Dr Randle, there are numerous different factors behind migration patterns of butterflies, but the weather and climate change are major contributors.
She noted that the increase in Speckled Wood into Scotland comes as part of these changes in their more natural Yorkshire habitat.
Dr Randle explained: “It’s moving northward because of climate change, and its expansion in range is vastly in Scotland because there is more woodland than there is in Yorkshire.
“This suggests climate change is driving species distribution in helping them moving further northwards. This can be mitigated by the availability of habitat.”
However, its not all bad news for Highland Perthshire’s butterfly species, more species of butterfly are increasing in numbers than less.
Painting this picture, Dr Randle said: “In Scotland, you’ve got sixteen species, which in the longer term are showing increasing in population trends, and we’ve got nine species which are negative population trends, and this data goes back to the nineteen seventies.”
Furthermore, Dr Randle says that these numbers could be different this year for many reasons, she explained why this could be: “The fall in butterfly numbers this summer may be due to a number of factors.
“An unusually warm spring led many species to emerge earlier than usual. So we may have only caught the tail-end of the flight period for many species during this year’s Big Butterfly Count.
“It’s important to look at butterfly trends over longer periods, so our scientists will be using these results alongside our other datasets to get a clearer understanding of what is happening.”