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

Ellerburn Banks calcareous grasslands are succeptible to drought and although drought resistant species prospered those there were not significantly decreased . Overall numbers were down 11% whiel county waise were up 9% but it was a mixed picture. The big winners were Marbled White and Meadow brown that have thrived in last years hot summer and this year very hot June.  Speckled wood did surprisingly well as they did across the whoel of Yorkshire in likely their best year ever along with Brimstone and Red Admiral. Drought sensitive Ringlet and Small Heath suffered badly but Common Blue was  even worst . Wall and Dark-green Fritillary suffered  badlyeverywhere . The vanessids all did badly ( apart from Comma) and only in the dales  did we see the beginning of recovery of these species.  

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.