Pearl-bordered Fritillary 

 Mark Searle 

How have our butterflies fared this summer ?  A review of our monitored sites for June and July  

     After a very poor spring and a diabolical July we could be forgiven for thinking it couldn't get any worse for our butterflies. Quite the Opposite! June is the critical formative month and this year's heat was highly beneficial for maturing caterpillars and pupa with half our summer species doubling in numbers against previous summers leading to a 37% overall increase, potentially making this a record year. The graphic below illustrates the change in abundance this summer against previous summers and shows the fortunes of species but we can also translate that into insect numbers to illustrate better what we actually see: 


    Meadow Brown is always our most numerous species every year, and this summer,  numerically, saw the largest increase . It didn't seem to have suffered in last summer’s and this spring’s droughts. The species continues a pattern of increasing abundance in recent years and then by nearly doubling this year.  This same pattern also applies to Gatekeeper, Marbled White and Speckled Wood up by about a half this year after a series of good years. Both the two cabbage white species more than doubled being significantly bolstered by migrants. After a series of poorer years they just seemed to be everywhere, due to their mobility, often you could see ten in a vista which made them the most noticeable and placing them at the top of Yorkshire's Big Butterfly count.  Most interestingly species that had done badly for some years made a dramatic comeback particularly Small Skipper, nearly doubling and Small Copper trebling obviously favouring the hot dry conditions.  


  There is most certainly a pattern amongst the losers of the effects of last summer’s and this spring’s droughts. Ringlet much prefers the damp and although only 20% down in abundance  was by far the biggest numerical loser. The 2nd biggest numerical loser was Small Tortoiseshell after two years of booming in warm damp summers collapsed without a second generation last year and continues to struggle this.  Dark Green Fritillary is showing a precipitous fall to just a fifth of previous  again after booming for some years and being lost completely from our sites