The warm spring weather and the sunniest May on record has led to many butterfly species emerging early in the UK this year.
It is the first time this century that so many have been seen at this time, with sightings recorded for wildlife charity Butterfly Conservation including some very early dates for particular species.
The first Ringlet butterfly was reported on 24th May, three weeks earlier than usual, with the White-letter Hairstreak, not typically seen until 11th June, spotted on 29th May.
Two butterflies usually found in woodland in southern Britain – the Silver-washed Fritillary and White Admiral – were both seen two weeks early on 30th May, with the rare Large Blue making its earliest appearance ever this year.
Butterfly Conservation’s Dr Richard Fox, who compiled the figures, said: “Over the past 20 years, we’ve typically received reports of 39 species by the end of May, so 53 this year is amazing. Last year, for example, only 43 butterflies had put in an appearance by this point and the only other year to come close to the current total was in 2011, when 50 species had started to emerge by 31 May.”
Butterflies can adjust their emergence dates to suit our varied weather and to remain in sync with the plants that their caterpillars need to feed on. But this response to climate change isn’t always beneficial. Research has shown that emerging earlier leads to larger populations of species that have more than one generation each year, but for some, it can mean smaller populations.
Long spells of dry weather can also affect butterfly numbers as plants die back leaving caterpillars without food. “Prolonged dry weather is likely to be worse for butterflies that live in open habitats with soils, such as chalk downland. The Duke of Burgundy butterfly, for example, lays its eggs on the leaves of Cowslips and Primroses, which quickly become desiccated in dry weather.”
If you’d like to take part in the largest citizen science project in the UK, The Butterfly Conservation’s Big Butterfly Count runs between 17th July and 9th August. To sign up head to www.bigbutterflycount.org website or app or visit www.butterfly-conservation.org @savebutterflies
Main image: Large Blue (Keith Warmington)