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

Hawnby Hill craggs and steep slopes suffered badly from last years drought with overall numbers down 30% against 5 yr average. Fortunately the Duke of Burgundy came through with  loss similar to the downturn . Countywide site overall numbers were up  but here the drought had a much more profound affect. Drought sensitive Small Heath and Ringlet slipped to less than half and accounted for much of the loses . Dark Fritillary alsosuffered very badly here as it did everywhere along with all the Lycaenids and whites  Dingy Skipper also lost out  on dry sites.  This years hot June suited Meadow Brown and  pefectly and we saw a two thirds jump  and Wall  had there second best year after  2021, surprisingly as on many sites it was well down.  Red Admiral, Comma and Speckled Wood did well and countywide had their best year ever

Overall a very good year with numbers up a quarter  the biggest winners being the Browns . The Dukes were slightly up on last year if a bit down on the average they are about holding their own.  The skippers had a good year including  Dingy Skippers.  Brown Argus as in many places the migratory form had an exceptional year and spread widely.  Small Tortoiseshell was down on  the boom of last year but still good against the average  while Comma boomed  almost universally this year.. not here.  All the Browns had a good year  and although Small Heath was well down on last years boom was still well up on the average and Wall hung on to the big increase seen last year. 

2021 was a relatively good year again beating the next best 2019. Duke of Burgundy was a bit down on its 2019 peak but still up on teh average as were most other species apart from teh two cabbage whites which had a poor year at many locations.  In contrast Speckled wood had a pretty disasterous year, we can only speculate that the drought of spring 2020 has had a lasting affect. Stand out species are wall with  numbers more than doubled along with small heath having its best year for some time. Teh smal tortoisesheel boom continues as it does in most locations. It was one of te few sites to see comma improved as it was apretty disasterous season. Unfortunatly the demise of teh common blue reported last year continues down a qurter of its best in 2019 . Most of teh total increases were in Ringlets nearly doubling and teh site bucked other sites in having a annual increase across all species of near 30% over average

The early part of the season was dominated by the effects of the pandemics with the first walk when restrictions were lifted in mid-May.  Adjustsments were needed  for the early  period:  Dingy Skipper +8, Orange Tip +5, Green Hairstreak+14, Duke of Burgundy +65, Peacock +18, Speckled Wood, +3 Wall Brown+4 . This was a bit of a guess with the Greenhairstreak already finished and Duke of Burgundy  just past its best on this early site.

Despite the adjustments it was not as good a year as in 2019 for our more common species with Common Blue having a particular disaster. The Browns and Whites  had a poor year although Dingy Skipper was well up as in other locations and Wall and Small Heath suffered less so prefering the fine leaved grasses. The drought conditions would be the most likely culprit on these thin scree soils. However most noticeable is the improvement in Small Tortoiseshells also reported in Yorkshire