We have had two reports recently of Glanville Fritillaries in North Dorset!The first came in on 1 June, from Melbury Down, and the second on 6 June from Compton Down.
Mark Pike sent us a couple of shots of the butterfly on Compton Down, so we can see that it is a Glanville, but sadly, it is almost certainly a release.The only place in the UK where you are likely to find Glanvilles is the Isle of Wight, though the Butterfly Conservation website does show a few other scattered sightings in the 2010-14 period, it also states the species is restricted to the Isle of Wight.
We are always rather sad to see this sort of release: the individual butterfly will hopefully lead a normal life, but it will not be able to mate and breed, so it just dies without having fulfilled its potential. Introductions or re-introductions of species are much more difficult than you would think on the surface, requiring in-depth knowledge of the butterfly, management of the site prior to the introduction and management of the site once the release has happened. The only really successful release in recent times has been the return of the Large Blue to Somerset, brought about by Dr Jeremy Thomas after much study and preparation.
We note that this is not the first time Glanvilles have been released: in 2000, they were found around the quarry on Clubmens Down and along the Wiltshire chalk downs. This seems to prove that this type of random introduction does not work: we have not been inundated with Glanville sightings over the last 19 years.