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

Malham was  down in overall numbers and like pretty much universally elsewhere the damp loving species were badly hit by last years heat. Numerically the biggest losers were Green-viened white, Ringlet and Small Heath . This was somewhat counteracted by a 80% increase in Meadow Brown again this was pretty much universal and  good numbers again this year of Small Skipper who tend to love the dry and heat  The other big loser  was Small Tortoiseshell which again has almost universally declined but Peacock which tanked countywide for a second year, here in the hills shows very strong signs of recovery up into the hundreds.  Its important to note this is a remarkable year in that Holly Blue appeared for the first time and Speckled wood has been present as singletons these last two years.. signs of things to come. All the whites tanked apart from Orange Tip.  Dark-green Fritillary recovered somewhat from last last years big dip but this is against the trend this year apart from  on sites at the highest altitudes Malham being the highest at 400m. 

Counts over the last decade have near enough doubled  mostly due  large increases in the grassland species, in particular, Ringlet , Small Heath and Common Blue.  Even the warmth lover small skipper has now made it to 400m altitude in the last  4 years and numbers this year  are double last.  Brimstone has also been seen for the first time last year . The whites had a poor year  although Orange tip staged a come back after a very poor 21  and its trend long term is very much upwards. Brown Argus is only seen spasmodically and not this year as  it has been a poorer  year on most upland sites due to drought.  Green Hairstreak  peaked in 2018-19 and was somewhat down against the average. Meadow Brown had a very good year while the other browns were down. Small Heath had a exceptional 2020 but this has been followed by two poorer years. Vanessids had a terrible year as they did in most locations due to the drought and heat.

After three very good years 2021 was a bit of a fall 22% down . 2019 standing out as exceptional in the last 5 years.  Small Skipper and Small Copper are showing a significant  increases  over the 5 year term in contrast to much of Yorkshire . The Whites have steadied down after the boom years 2018-19 as have Oraneg Tip. Brimstone made an appearance in 2021 which is encouraging for this spreading species. Common Blue had a very significant rise last year and is a little down this year back to their pre peak numbers. Peacock numbers have dropped back in common with most transects  and Comma has not been seen for 2 years and had a exceptionally bad year on most transects . Dark-green Fritillary numbers  peaked in 2019 and have dropped back a little while elsewhere they had a good year . Ringlet had a poorer year while Small Heath wasnt bad with second highest year and has been one of the exceptional  winning species in Yorkshire in 2021.   The  Small Tortoiseshell boom continues as elsewhere but in contrast to other areas Red Admiral did well. Northern Brown Argus fluctuiate in numbers with no clear trends while in most of Yorkshire they increased substantially.