Warm weather attracts rare migrant butterflies and moths

Increased sightings in the UK suggest that exotic species of butterflies and moths from the continent are attempting to colonise southern England after the warm summer and mild autumn.

The long-tailed blue is a rare migrant butterfly from Europe. This summer, it has raised young across a considerable area for the first time – sightings have been reported in Dover, Kent, Sussex and Wiltshire.
 
The largest of the underwing moths, the Clifden Nonpareil, is a continental moth with vivid underwing flashes that it uses to ward off predators. Recent sightings in Dorset, Hampshire and Sussex have led to speculation that this species is also colonising the UK.
 
Les Hill, the Dorset County moth recorder, said: "Clifden Nonpareil is one of the most charismatic of British moth fauna, and is on every moth recorders’ ‘wish list’.

"As the name ‘Nonpareil’ states, it is peerless and has no equal. To record one in a lifetime is the fulfilment of an ambition; to record them every year in my garden is just remarkable.”
 
Before this summer, the large Rosy Underwing moth had only been seen on 10 occasions in Britain. It is now thought possible that this moth could be locally resident in England.
 
Richard Fox, surveys manager at Butterfly Conservation, said: “The hot summer enabled long-tailed blues and other migratory butterflies to spread northwards into Britain, capitalising on opportunities to breed here while the weather remains warm.

"This species probably won’t survive the forthcoming winter, but it seems likely that the stunning Clifden Nonpareil and possibly even the Rosy Underwing, have already established footholds in southern England.”
 
As well as increased sightings of rare migrants, the traditional autumn moth migration is also well underway. The delicately patterned vestral moths entering the UK have increased in number and distribution, with sightings as far north as Scotland and Northern Ireland. 
 
Image courtesy of Leigh Prevost, Butterfly Conservation.