Butterfly Conservation Yorkshire

Fordon Chalk Banks

Hunmanby

Bridlington

Site Details

Privately owned with permission for Butterfly Conservation Yorkshire to maintain site

Recorders: Kerry Metcalfe Distance: 1718m Altitude 98m Walk time: 1hr

This SSSI and surviving relic of semi unimproved Limestone grassalnd which was once typical of the Yorkshire Wolds is one of Yorkshire's best butterfly sites. It is excellant for Dingy Skipper, Brown Argus, Small Heath Wall and Dark-green Fritillary.

Fordon Chalk Grasslands comprise one of the most varied grassland systems, in terms of their floristic richness, aspect and management regimes, remaining in the Wolds. The site comprises a disjunct series of grasslands in the dry valleys of Cotton Dale, North Dale and East Dale, centred on the village of Fordon. The grassland communities include heavily-grazed, short-turf areas dominated by sheep’s’ fescue Festuca ovina and red fescue F. rubra, mixed grasslands with fescues, sweet vernal-grass Anthoxanthum odoratum, hairy oat Avenula pubescens, quaking grass Briza media and crested hair-grass Koeleria macrantha, and areas of course grassland with upright brome Bromus erectus and cock’s-foot Dactylis glomerata. Many areas are extremely diverse botanically, with an abundance of characteristic herbs such as clustered bell-flower Campanula glomerata, carline thistle Carlina vulgaris, woolly thistle Cirsium eriophorum, dropwort Filipendula vulgaris, rockrose Helianthemum nummularium, purging flax Linum catharticum, cowslip Primula veris, salad burnet Sanguisorba minor, devil’s-bit scabious Succisa pratensis and thyme Thymus praecox. Additionally many less common species occur: pyramidal orchid Anacamptis pyramidalis, kidney vetch Anthyllis vulneraria, purple milk-vetch Astragalus danicus, frog orchid Coeloglossum viride, bloody crane’s-bill Geranium sanguineum, felwort Gentianella amarella and saw-wort Serratula tinctoria. Gorse Ulex europaeus and hawthorn Crataegus monogyna scrub is present on many of the slopes, and in places forms dense stands.

Sections

The route starts from the style on the raodside up the stoney track to the BCY sign as you enter the banks near the North west corner with hedgerows either side and Speckled woods and other browns predominate. S2 was the original section restored by removal of scrub by volunteers and where Wall is most likely to be seen in good numbers along with high numbers of Smal Heath and Marbled Whit. S3 was restored next and Meadow Brown decreases alot but Dingy Skipper appear in numbers through to S5 which was unrestored til 2020 and they largely disappear.

A slow discent via S6, S7 to S8 in the far east where Small Heath, Wall , Marbled White and Dark-green Fritillary are at their best. Following back to the start along the bottom of the bank shows numbers very much higher than the higher areas with Dingy Skipper and Common Blue being extremely numerous in S9, a newly restored section and S10 through the hedge into the older restored area where Brown Argus is very numerous as are Dark-green Fritillary. S12 and S13 comes into the shade of the woodland and Speckled Wood predominate but few other species

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

Transect reports

Fordon did very slightly better than the county average mostly because Marbled white numbers were better and Ringlet nearly doubled on last years both benefitting from a recovery from the last two years of drought . In addition Brown argus was very little affected by the diabolical conditions in common with the northern species which showed a big increase but also feed at altitude on Rockrose. The main losses are with the dry loving meadow Brown and Small Skipper but also Small Heath which had its worst year ever but still proportionally better than elsewhere. Wall had a very bad year everywhere and unfortunately it looks like Dark green Fritillary may have gone extinct on the Wolds this year. Peacock as everywhere is making a very strong recovery but unfortunatly this is not tru of Small Tortoiseshell with none seen

Results: 2023

County wide 2023 results reflect the 2022 and 2023 spring heat & 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%.

Fordon's dry steep chalky slopes did better than expectatoions as many such sites suffered way more but still it was the lowest year so far. It follows the county trends with Rockrose Brown Argus down somewhat along with Dingy Skipper, Common Blue and Small Copper and the damp favouring GV White and Orange Tip. Brimstone saw a healthy increase in common withe county giving it its best year ever. Marbled white has its best year ever along with Comma and of course Red admiral. Luckily the Dark -green Fritillary persisted but on many sites it was wiped out so hopefully it wil bounce back. Wall suffered everywhere with a similar decrease to here of 60-80% loss. The losses of damp lowing browns, Ringlet and Small Heath, almost equalled the increases in Meadow Brown and Marbled White. It could so easily have been a bumper year just a pity about the drought!

Results: 2022

A slightly better year although the banks did suffer in the drought conditions, Bucking teh county trend Skippers were up and Brimstone was pretty universally up this year on our sites. Brown argus and Common blue both suffered somewhat, as did teh smal ltortoiseshell and Peacock which were universally down with some huge losees in teh summer generation which in most localities failed to materialise at all. Dark Green Fritillary was down as it most across the county while speckled wood and wall were both up again following county trends. marbled white had a good year and was only just beaten by Small Heath of the Brown only Meadowo Brown suffered . Good to see gatekeeper return after a few years and this species has had a very good year with dispersal.

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