www.ukbutterflies.co.uk

Not a species you hear much about in these forums, mainly because it is an absurdly rare migrant to Britain. It is also getting scarcer in Europe in general, while its more sedentary cousin, the Provençal short-tailed blue (Everes alcetas), seems to be on the rise.

Short-tailed blue is not resident anywhere near my local patch in Switzerland, either, and until today I'd never even seen one in the country, despite examining dozens of alcetas every year in the forlorn hope I might pick one up. I was therefore thrilled to see at least half a dozen males and a female today at a site I visit regularly throughout the year (so I'm sure they don't breed there). They were messing in with alcetas and also zooming around all over the place, so I couldn't count very precisely and it might have been more - they are very similar in flilght. Certainly, it wasn't just one or two - these were tourists on a package tour.

It was probably local conditions and winds that brought these butterflies to me (they do breed in the far west of the country); but given I've never seen them before, and suddenly a whole pile pitch up at once, it does give rise to the hope this is a short-tailed blue year! Now is precisely when migrants are generally seen in England. You've been warned...






Guy

Interesting... thought I'd been lucky/ unlucky in seeing just Provencal on each visit to Southern France. This year I saw one female Short Tailed... hope they are not declining.

Was that on your Pyrenees trip, Paul? I'm interested to know because I don't think (any more) I've ever seen short-tailed in the Val but I did wonder if it was because I was always there between broods. I do generally see Provençal short-tailed there (though I didn't this year because the two places I see it had both just had their annual mowing). If you saw a female during that same period, also in the mountains and not so far away, that means my brood theory is wrong.

Guy

Sorry, not Pyrenees, but 42 27 36.07N 2 37 58.37E @ 319m, Arles sur Tech, don't think that ruins your theory
PS.. love the fresh male shot

Just to follow up: I've spent a few days in France with Tim Cowles and short-tailed blues were everywhere! They outnumbered Provençal short-tailed by a considerable amount. I saw them laying on several different plants, all of which occur widely in England and it's a bit of a mystery to me why this butterfly doesn't fly there.





Guy

Well, if it appeared, call me cynical, but it would be hailed as a release and someone would do their best to discourage it from establishing in the name of science!

You old cynic!

If it were going to establish itself I think it would have done so long ago. The limiting factor doesn't seem to be climate, as the species is apparently resident just across the channel, and clearly not foodplants either. But blues have very complex ecologies and there must be some reason.

Nevertheless, this is clearly a very good stb year - so keep your eyes peeled!!

Guy

padfield wrote:...Nevertheless, this is clearly a very good stb year - so keep your eyes peeled!!

Guy

Yeah - they'll swim over here!