A group of committed TDEG members have taken surveys of butterflies down Tideswell Dale every year for the 26 weeks of the season since 2021. We now have a much larger team of ten pairs of surveyors, including our youngest surveyors so far (brilliant work from Alfie and Ellis). TDEG is grateful to all the volunteer surveyors.
TDEG also appreciates the tremendous support we have had from Ken Orpe of East Midlands Butterfly Conservation for helping us set up our butterfly observing transect in Tideswell Dale, and assisting us every year in identifying species and entering them into the national database.
Since surveying began in Tideswell Dale in 2021, our volunteers have recorded 27 species of butterflies. In 2025, 24 species were seen (see ‘All species..’ section at the end of this post) including four rare or declining species. After a low count of total butterfly numbers last year, the better weather this year helped numbers bounce back.
Rare species
Four species noted as rare or declining in the UK Biodiversity Action Plan were spotted by our surveyors in Tideswell Dale this year. Sharp-eyed surveyors saw two of the small, moth-like Dingy Skipper fluttering around in the grass. Much easier to spot is the magnificent bright orange Dark Green Fritillary (its name comes from the colour of a part of its underside) which had a good year this year with 20 individuals seen – more than in any previous survey year on this site. It was also a better year this year for the Small Heath (29 seen). Two of the elegant Wall Brown butterfly were also seen.
Next year we will also be keeping our eyes peeled for the two rare species seen in previous years that did not show this year: White Letter Hairstreak and Brown Argus (Peak District Race).
Was the weather good for butterflies in 2025?
Our surveyors take it in turns to go out looking for butterflies once a week, and try to go on a day which is warm and sunny, with no more than moderate winds and not when it is raining, to see as many butterflies as possible. On a sunny day, the UK Butterfly Monitoring Scheme advise us that butterflies are more likely to be seen flying with temperatures of at least 13 degrees Celsius. When its not sunny, surveying is better with temperatures of 17 degrees Celsius or above.
These Buxton climate data, calculated by Michael Hilton, indicate that April and May were the sunniest months since butterfly surveying began at Tideswell in 2021.
April 2025 also had the hottest average temperature in the last five years. The table shows monthly average temperatures in degrees Celsius.
August 2025 was the driest in the last five years.
Are butterfly numbers increasing in Tideswell Dale?
With only five years of data we cannot say what the long term trend in butterfly numbers is in Tideswell Dale. Landowners are managing parts of the site with butterflies very much in mind, for example by ensuring there are open areas for them to feed.
The graph below shows that the number of butterflies seen in Tideswell Dale in 2025 was 140% higher than in 2024, and about 40% above the average number seen here. Across the region as a whole, the increase in butterfly sightings on monitoring scheme walks in 2025 has been about 120% more than 2024 (although still only returning to around the average, after last year’s disastrous records).
How are butterflies doing nationally?
All our butterfly records are entered in to the UK Butterfly Monitoring Scheme national database, which this year celebrates 50 years of collecting butterfly data. It monitors over 3,500 sites in the UK and this method is now used in 30 countries around the world including Spain and New Zealand.
Nationally, we can see that numbers have, sadly, decreased by 18% since 1976. Specialist species have declined by about one third, but some generalist species, notably the Whites, are doing better and perhaps benefiting from climate change (David Roy, Head of Biological Records at UK Centre for Ecology and Hydrology, UKBMS 50th anniversary event October 2025).
The database is used to inform national policy and in Tideswell Dale to enable landowners to see whether conservation practices are effective. The annual survey help us see which species are in the most trouble, whether any are increasing and to notice any new species arriving.
All species seen in Tideswell Dale by TDEG volunteer surveyors in 2025
The species seen in 2025, with photos where readily available (sometimes from other sites in the Derbyshire Dales) were: Small Skipper, Large Skipper, Dingy Skipper, Brimstone, Large White, Small White, Green-veined White, Orange-tip, Green Hairstreak, Small Copper, Common Blue, Holly Blue, Red Admiral, Painted Lady, Small Tortoiseshell, Peacock, Comma, Dark Green Fritillary, Speckled Wood, Wall, Gatekeeper, Meadow Brown, Ringlet and Small Heath. (Rare species in bold.)
The White Letter Hairstreak, Brown Argus (Peak District Race) and Silver-washed Fritillary have been recorded in previous years of the survey, but were not seen in 2025.
