Several other migrant moths, including the gigantic convulvulus hawk moth with its four- inch wing span, are also here in large numbers. So is the Clouded Yellow butterfly. Warm days and little rain have suited them.
"It's got all the hallmarks of being an extremely good year," said Dr Paul Waring of Butterfly Conservation, a wildlife charity. "As far as the migrants are concerned, the best is yet to come." Throughout the summer, numerous lepidoptera move north through Europe, building up their numbers spectacularly with three, and sometimes four, life-cycles - unlike species resident in the United Kingdom, such as the orange tip, which breed just once a year.
Large numbers of the painted ladies and silver y moths flew in from Europe early in June, helped by strong winds from the south. Their caterpillars have become adults which have now had their own caterpillars, so a further burst of adults is due.
However, very few will survive the British winter. The exception is the Red Admiral, which is also having a good year. Mostly a migrant, this species is known to "back-migrate", some insects flying south to warmer climes in the autumn.
Several butterflies which are permanent UK residents are also thriving this summer, including the peacock, small tortoiseshell, the gatekeeper and the Holly Blue.
If Britain's climate is warming up, then several Continental species, that are occasional summer visitors, are likely to join them. The Bloxsworth snout moth, for instance, used to be classed as a migrant, but in the past few years has bred well in Devon.
The Forestry Commission has warned, however, of the effects in Scotland of the pine beauty moth which can kill commercially-grown trees and spread fast through plantations.Reuse content