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A record-breaking finale to the 2025 butterfly season

2/10/2025

GH and BG completed Transect 26, bringing this year’s butterfly season to a close under fine, warm skies. While the overall count was modest at 23 – an average score for week 26 – the transect still held plenty of interest. A lone Brown Hairstreak put in an appearance on Great Parsons Field, while most of the activity was centred on Fames Rough and Coneyboro Hill.
The butterflies seen up close looked remarkably fresh, suggesting newly emerged individuals: Common Blues, Brown Argus, Brimstones and Small Coppers all showed off their bright colours. We also recorded a late-season Peacock, the first since July.
But the real story of 2025 lies in the season as a whole. With persistently high summer temperatures, this became our busiest butterfly year since records began in 2016. We counted an astonishing 7,140 butterflies, comfortably surpassing the previous high of 5,763 in 2019. Average counts per transect jumped from 240 in 2019 to 275 in 2025, a leap mirrored in reports from across the UK, confirming 2025 as an exceptional butterfly year.
Highlights weren’t limited to big numbers. We had three rare sightings of Silver-spotted Skippers on Great Parsons Field, a species of national conservation interest. A UKBMS team, intrigued by the record, carried out a detailed survey and discovered 18 Silver-spotted Skipper eggs on sheep’s fescue grass, the larval food plant. Their verdict: the site is highly suitable for supporting a permanent colony.
And, in July, another first: two Purple Emperors soaring over Hill Wood Field – their debut appearance in nine years of transects.
From record-breaking counts to rare and regal encounters, 2025 will be remembered as one of our finest butterfly years.

Count details:
7 Common Blue
4 Brimstone
4 Meadow Brown
2 Brown Argus
2 Small Copper
1 Brown Hairstreak
1 Large White
1 Peacock
1 Speckled Wood

Count summary:
23 butterflies from 9 species.

For more info on these species visit butterfly-conservation.org

Click here for a spreadsheet
detailing the counts of 2025 and previous transect seasons.