Clouded Yellow butterfly - Colias croceus

Every so often something nice happens... today I want for a walk around the Millennium Wood at Castle Camps and I spotted this!  A Clouded Yellow butterfly flitting about and feeding on Lesser Hawkweed flowers...

Spent a bit of time crawling about hoping to get a halfway decent shot and managed this.

I can't remember ever seeing one of these before, they are migrants from Europe http://www.ukbutterflies.co.uk/species.php?species=croceus