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

Leyburn was slightly down on its 5 year average but still pretty good and only really pipped by 2018/19 peak.  Another site seeing the remarkable return of the Wall these last two years. On its well known sites it has done badly  but  this site  shows significant improvements in other respects with Small Heath continuing to increase at a good pace while for most sites these last two years have been poor , in addition Small Skipper had its best year ever here while although rising long term has had two bad years in the drought.  Lots of positives. 

 The longer term annual trend is for increasing counts and 2022 comes in as second highest year after the big peak in 2019. Interestingly our  scarcer species are responding very positively with Small Heath  and Common Blue seeing a big come back.   Both the skippers were well up which seems to be the case on many Dales  sites but the reverse of the lowland. In common to most other places apart from upland sites the Vanessids were universally down due to the heat and poor nettle quality driving them into very early hibernation and  only comma managed a second generation successfully.  Its great to see the return of the Wall after some years and this species apears to have had a good year with lots of dispersal going on. Small heath was down on last year but still a tad up on the average. The other Browns all werw all up about a third including Speckled Wood and follows the county trend.

Despite the weather the year ended with broadly similarto the 5 year average if a tad down on 2020 and with 2019 being exceptional.

The patterns are somewhat similar to elsewhere in yorkshire  with  Small Tortoiseshell and Small Heath  both having very good years but also decreases in many other species particularly Large Skipper  Small White, Red Admiral, Peacock,  and Speckled Wood.  Comma in particular had a very bad year almost everywhere. 

Where it bucks the Yorkshire  trends is with Small  Skipper, Common Blue and Small Copper increasing  and Orange Tip decreasing . we do know the summer in NW quarter of the County was warmer and sunnier than average and significantly  different to most of Yorkshire.  

Numbers are well down compared to the good year of 2019. 2019  was characterised by the Painted Lady invasion and numbers of Meadow Brown recorded doubled compared to normal however this years results are very close to average and not the disaster forecast by some.  Both species have returned back to more normal levels but there is little signs of drought effects of the dry spring seen on other transects.  However Green-viened White and Peacock numbers are also well down. In contrast Common Blue numbers which have colapsed on some transects showed a steady rise to good numbers . This could be because it is a damp site and the spring drought had a lesser effect.  Small Heath is showing a steady rise in numbers these last few years  and  Small Tortoiseshells numbers have more than doubled and are again a common butterfly after a few years in the duldrums as  on all  transects.  The skippers showed a good increase in contrast to some other dryer sites