Butterfly Conservation Yorkshire

Silpho Quarry

Dalby Forest

Site Details

NB This is a private site with no public access and permission is required from the land owner to survey

Recorders: Ian Popely Distance = 1000m Altitude 190m Walk Time 1 hour

This is a long-disused limestone quarry near Silpho. It was once wel known as a Duke of burgundy site but has noot been recorded here for many yearsThe track down to is interesting, with many wildflowers in the verges, including meadow cranesbill , knapweed , field scabiou and greater bellflower. The quarry floor was like a garden with a fantastic display of late summer flowers, including the delicate lesser scabious in huge numbers.

The site has been scrubbing over for some years to the point it was not only degrading fast but getting difficult to walk the long established transect. With the co-operation of Carstairs who now manage the site Butterfly Conservation , Ryedale and Scarborough Nats and many other volunteers the scrub has been cleared and stumps treated to prevent regowth and the transect route fully restored. It wil be very interesting to see how the species fare from now on and the huge amount of work is expected to yield rewards and , maybe, one day, the return of the Duke.

Sections:

S1 hedgerow leads down to te site entrance and the gully is damp and yoelds very lareg numbers of Green-viened white Lareg and small Whites, ringlets Peacock and other vannesids but alos Wall brown. S2 is a smal meadow just above the site and yoelds a typical grassland species in fair numbers and Large Skippers.

S3 takes us to teh xcentre of te hsite with mor edap shade loving grassland species

S4 is a branch to the westeren edge of teh reserve and the steep descent into teh valley below but is scrubbed over and yields mostly speckled woods

S5 in the centre of the site

S6 takes us into agrassy sheltered gully with a profusion of grassalnd species and favoured by Marbled whites

S7-S8 takes us from teh far south of teh site upwards to teh western half with more marbled whites large skipper.

S9-10 are favoured by the skippers and Ringlets

Results 2024

Countywide, after a warm winter April turned cold, very wet and dull and everything just about stopped and it was near impossible to transect walk all month. By May there were already losses among our spring species being down a third in numbers. June brought Arctic winds, a complete reversal of the Hot June of 2023 when nine species reached all time highs here and across the UK. For the first two weeks of this June temperatures were 8’C cooler than in 2023 around a frigid 9’C with only 5 good days of sun at the end of the month. The first three weeks of July had the same theme of cool and damp with 5 warm sunny days at the end. Transect walking for many was very difficult. The persistence of the cold and damp over such a long period had a devastating effect with numerically two thirds of our butterflies in the critical later stages of their development; mortality was very high. It was also one of the longest June ‘Lulls’ lasting from late May to the beginning of July. When the main flight season did arrive it was slow to build up and there was no usual peak. Better weather in August helped save the second generation and very unusually numbers actually went up at the start of September.

Losers

For many species it was a triple whammy after the heat and droughts of the previous 2 years and last July’s poor flight period this year made it a perfect storm. Overall, annual numbers were down 41% against the average and 45% down on last year. Half our species were down more than 50% and a quarter down more than 70%. The Lycaenids, Vannesids and the Fritillaries were amongst the worst affected. Many transect walkers did not see a single Common Blue, Small Copper, Holly Blue, or Brown Argus until late into their 2nd broods.. Four of our long term declining species Common Blue, Small Heath, Small Skipper and Green-veined White had their worst year ever recorded.

The Winners and less bad losers

Northern Brown Argus had an exceptional year up near 50% Other species bucking the trend were Brimstone and Marbled White. The damp loving Ringlet on many limestone/dry sites were up a half while on most wet sites they fell by a half. However if it wasn’t for Ringlet holding up the overall numerical losses, this year would have been significantly worse. It often happens when Meadow Brown has a very poor year, like this one, Ringlet does proportionally better, and vice versa in a warm year.

It has all happened before… many times.

It was our worst year since 2016 but nearly as bad as 2009 when numbers were down 50%. 2024 comes after a run of 6 relatively good years since 2018 along with rapidly rising temperatures including 2 of our hottest summers which were followed by two of our best butterfly years in 2019 and 2023. It is likely 2024 was a blip

Silpho Quarry did a bit better than the county average mostly due to Marbled white increasing and Ringlet holding up well which is typical of a dry calcareous grassland recovering from 2 years of drought. Other stand out a Large skipper, Common Blue which is down to a rapidly improving habitat for them as well as relief after the drought years . peacock also bounced back after the droughts and had a stronger showing. Small Tortoiseshell just held on at very low numbers.

Transect reports

Results 2023

County wide 2023 results reflect the 2022 Heat and drought with Small Tortoiseshell and Peacock nearly halved for the second year against their 5 year average. Red Admiral arrived in force in July and took advantage of soft nettle growth of the rains and had their best year ever. Drought sensitive species on thin soils were badly hit, particularly Dark -green Fritillary and Northern Brown Argus but also Ringlet, Green-viened White and Small Heath. Less drought affected species along with the hottest June on record built even more on gains last year leading to Comma, Brimstone, Holly Blue and most Browns having a fantastic year reaching all time highs. A increase of 9% overall was mostly due to sheer numbers of Meadow Browns and Gatekeepers ment 2023 nearly pipped 2014 as best year in modern times. Most noticeable was the large differeces between moisiture retaining mineral soils of the valleys and thin, dry limestone or sandy soils. A large number of damp grassland, hedgerow and woodland dominated sites benefitted hugely with 3 sites seeing more than 50% increase . A smaller number of thin, chalky, sandy or craggy sites did badly some down up to 25%.

Silpho Quarry has a good year although not as good as 2019 only because the vanessids were well down. The increase in numbers islargely down to meadow Brown and Marbled white both having cracking years which they did across teh county. Alos floowing county trends are booms iN Speckled wood, Comma Red Admiral and Holly Blue. Also doing well on thsi site Common Blue, Orange Tip and a resurgence in Dingy skipper. Big Loser were drought sensitive Green-viened white while Ringlet was just able to maintain its numbers although it lost out almost universally elswhere. Wonderful to see 3 species of Fritillary with Small pearls having quite a good year teh health of this site is no longer in any question. Well done.

Results 2022

Results are well up on last year which is encouraging but also we see the return of the Small Heath and Marbled White really beginning to strengthen and Dingy Skipper was well up bucking the county trend. The site's history is of slow deteriation with scrub cover over calcareous grassland so we have seen to some extent Speckled Woods replacing meadow browns and Ringlets. Despite this longer term we stil see a small increase in numbers

This year see orange tips and Smal whites having abetter year Large and Green-viened White having a bad year which is rather similar to elsewhere. Small Copper was a bit down but rather random but it is better than zero last year. brown argus had a good year or at least the migratory form on cransesbill did while the rockrose on limestone suffered in the drought . All teh vanessids are down but particularly peacock with only 1 seen after mid May it is difficult to believe that in 2014 there was a total count of near 300 . Tortoiseshell did a bit better here than most localities but only 2 were seen after the beginning of July. All teh browns except Ringlet saw a increase with marbled white in particular increasing on last years boom. Speckled wood tripled on last year in line with many locations but not enough to put it above the 5 year average.

Silver-washed Fritillary and Dark-green Fritillary are occasional vistirors to this site

Results 2021

A poorer year than of late and slightly down on elesewhere there are soem trends to pick out. The skippers are much less numerous as ere Small White which is prety much liek elsewhere Green Viened White loved our wet summer and was up as was orange Tip in line with most transects Holy Blue and Brimstone wer eabsent. Smal Copper and Common Blue alo s down as with other sites. Vanessids were wel down apart form tortoiseshell which were up again all inline wioth other sites Comma had a disaster as it du=id elesewhere. marbled white boomed as they did on virtually all sites but Speckled woods were down Silver washed fritillary and Small Heath were seen for the first time and Wall reappeared all had good years elesewhere.

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