Thorton le Dale
Recorders: Ian Popely, Graham Oliver and Paul Cogan Distance : 925m Altitude: 145m Walk Time: 45mins
Ellerburn Bank is a 3 ha. grassland site sloping south-east on oolitic limestone on the southern edge of the North York Moors near Pickering. Despite its modest size, it is one of the most extensive areas of unimproved limestone grassland remaining in the North York Moors . It was notified as a SSSI in 1983 and has been managed as a nature reserve by the Yorkshire Wildlife Trust (YWT) since 1966, having been informally managed for nature conservation perhaps for the previous decade. The flora and fauna of the site is exceptional for the region, with over 150 species of plant recorded including large displays of Cowslip in spring, orchids in early summer and Gentians in late summer . Flowering plants of regional note include Dropwort, Woolly Thistle, Saw-wort, Fly Orchid Ophrys and Greater Butterfly Orchid. The site is noted for its extensive Lepidoptera fauna , including butterflies of regional note such as Dark Green Fritillary and Dingy Skipper Erynnis tages, and the site also supports a population of Glow-worm Lampyris noctiluca. Management of the reserve currently consists of low-intensity winter grazing by Hebridean sheep and rotational scrub clearance.
The upper, northwestern margin borders an agricultural field and consists of a Bronze Age earthwork (a double ditch and bank) partially covered with Hawthor and Blackthorn scrub, S4 (record bank side only ) and S5 whilst the lower, south-eastern side bordered by forestry S7, consists of a patchwork of taller grass and Gorse following the lowest path. S1 follows the north east boundary dry stone wall and is favoured by Wall brown and Dingy skippers and lizards. The southern edge is sheltered and changes to isolated gorse bushes S3 returns to teh entrance and S4 follows the ditch southwards.
Small Skipper is having a bad time in Yorkshire but here it it significantly worse possibly due to the dry nature of the site and it follows the county pattern of the 3rd year of decrease. Large skipper although better than last year is also on a down. Dingy skipper follows the county pattern of being a bit down on the good years, Brimstone again follows county trends in being up . The whites dont follow the county trend being well up on this site while down in the county. However Orange Tip was well up as in the county trends . Small Copper showed a loss as in the majority of sites. Brown Argus was down on this upland limestone site as it was on other rockrose sites while the migratory form was well up on its alternative foodplant cransebill down in the lowlands. Common Blue was also down but held its ground on other sites. All the vanessids were down apart from Comma which was well up and follows trends across the county with neither Small Torts or Peacock producing a second generation and later having a very grim time, Dark Green Frits were also down as in other parts of the county. Speckled Wood boomed as they did elsewhere particularly in later broods. Meadow Brown boomed and Ringlet was well up more so here than in other sites . In common with the county Small Heath was down along with Marbled White,
Overall numbers were down somewhat compares to the boom years of 2018-19. The large skipper did not reappear after a rapid fall last year and even teh Dingy skipper was down possibly the effects of last years drought spring. Green viened white had a good year as tehy tend to enjoy a wet summer. Small Copper was also well up but Brown Argus had its best year since 2018 . common blue in contratst continued a trend of decreasing . The vannessids in common with most transects had a bad year particularly Comma. Speckled woods and most of the browns were down apart from Small Heath that had a boom similar to other transects and Ringlet had its best year for some years. Unfortunately Wall was not seen thsi year after better numbers last year but we know they tend to hate wet summers like 2020-2021.
Things in general still in good shape.
After two cracking good years numbers have fallen back only marginally and held up well during teh poor summer of 2020 but it may well have benefitted from the long hot dry spring. Skippers were down along with Green viened white and Speckled wood which could be related to the spring drought but its great to see the Wall back in good numbers and Small Tortoiseshell after years in teh doldrums have a boom year along with Small copper and to a degree Dark Green Fritillary. A good deal of estimating had to be done for the spring species so its difficult to comment . Overall things look in good shape.