Red Admiral (Vanessa atalanta)
I always look on the Red Admiral as a an 'English' butterfly but in fact they are quite migratory. They seem more hardly than the Painted Lady and some manage to successfully hibernate and we see them in early spring. By April and May we start to see an influx from the warmer south and by the late summer/early autumn we see the offspring emerge those early arrivals.
Interestingly, there is some evidence to suggest that there is a southerly migration in autumn to warmer climes, just like some bird species.