Friday just gone was a day of Small Tortoiseshells. My garden in West Cornwall was visited by tens of them enjoying a late summer feast on the buddleia – I was glad I hadn’t pruned it back already.
But then Saturday and today, Sunday, there was barely a Small Tortoiseshell in sight. Instead the garden was full of the striking beauty of several Red Admirals, again nectaring on the buddleia, but also seeking out ivy flowers and late summer bramble.
Butterflies seem so delicate, it is easy to forget that several species accomplish great feats of migration. The strong-flying Red Admiral (Vanessa atalanta) may have a small resident population in the south of the UK, but most of those we see each year have arrived from Europe and North Africa. The females lay eggs (usually on common nettle (Urtica dioica)) and UK-bred butterflies emerge from about July, but their numbers are swelled by several further waves of immigration during the summer. You can see them as late as October, occasionally later.
Our winters are generally too cold for this species to survive overwintering, possibly apart from the warmer south of the country (including Cornwall). Many adults will therefore attempt a southward migration as the weather cools. On a wildlife boat cruise out of Falmouth recently, while I was of course thrilled by the sunfish and porpoises, I was also delighted to see two Red Admirals a fair way out from shore, determinedly heading south away from the coast.
I hope they made it.