Large Tort in Dorset

[Gruditch]

Ha Grumpy Kipper, Guy agrees with me, an English LT, descended from the successfully hibernating LTs, around the Poole / Swanage area.


Gruditch

[Neil Hulme]

Hi non-grumpy Gruditch
That's a bit of a 'leap of faith' is'nt it? Belief that they're likely to be the product of man's intervention, to now a UK breeding population! I would like to believe that it's true, and I very much hope that this will become the case. At present, there's no hard data to support the latter hypothesis, although that doesn't mean that it isn't happening as yet. As far as Guy's comment is concerned - have I ever seen a specimen of either an undoubtedly migrant butterfly or moth retaining it's full (at least as discernable from that photograph) complement of body hair and scales? Well yes, a very, very large number! Would we be asking the same question of a Painted Lady, Red Admiral, Clouded Yellow, Hummingbird Hawkmoth, Silver Y etc etc? Probably not! It would be very interesting to hear a point of view from someone else that's actually plotted the geographical distribution and timing of these occurrences, relative to other migrants. But I think we're just going to have to agree to disagree on the subject and lay the matter to rest. Time to move on to another topic!
Neil

[Jack Harrison]

Sussex Kipper mused:

....retaining it's full (at least as discernible from that photograph) complement of body hair and scales? Well yes, a very, very large number!

Now wearing my (retired) aviator's cap, flying objects do not often (Qantas excepted ) sustain damage while in the air; damage occurs when in contact with the ground, ie when crashing. Butterflies probably sustain little if any damage while actually in the air but get most of it from contact with foliage and other surface objects.

So there is no reason why a migrant butterfly that takes off from Northern France and then flies across the Channel shouldn't arrive in England in pristine condition. This doesn't of course help the debate one way or another as to whether LTs in southern coastal counties are immigrants or native born.

And well done Neil on your second LT. You have now seen twice as many as I have.

Jack

[Matsukaze]

It is illegal to release species extinct in the UK without a licence - Wildlife & Countryside Act 1981 I think. The legislation was probably aimed more at releases of wolves, wild boar etc than butterflies though.

Do Large Tortoiseshells migrate both before and after hibernation, or predominately at one time, like Camberwell Beauties?

[Padfield]

I think their behavioural patterns are rather similar to Camberwell beauties. In spring, large tortoiseshells emerge predictably at favoured hibernating sites (chosen for the presence of foodplants and a suitable breeding environment) and are then conspicuous butterflies there for a couple of months. They can be seen defending territories, interacting with each other (I've never seen them mating though) and so forth. In the summer, by contrast, the species can easily pass you by. You encounter butterflies individually, not in groups, even at those sites where they were common butterflies in spring, and the total you see is a fraction of what you see in the spring. The explanation seems to be that some summer butterflies feed up and go into hibernation at the breeding site quite quickly, while others disperse, find other suitable breeding sites and then go into hibernation. Thus, summer is taken to be the principle dispersal time. In southern Europe an extra, non-hibernating generation is squeezed in, a little like comma, and it would seem to me likely that in good years this early generation would be prime candidates for dispersal, but I have no evidence for that.

Points taken about the possibility of an LT crossing the channel and arriving in pristine condition. France is really not very far away - almost local. On longer flights butterflies do lose body hairs, for whatever reason, but I accept this is unlikely to be relevant in Dorset, near the coast.

The last few years have seen a resurgence of LT in many parts of Europe. Let's hope you're witnessing the beginnings of a new LT era in Britain.

Guy