Scarce Tortoiseshell sighting!

[Pieter Vantieghem]

the female illustrated (photos Perry Fairman) might be a better match for Large Tortoiseshell not Scarce (the paler patches adjacent to dark splodges).
Jack

I think you are referring to this picture



In my opinion scarce tortoiseshell is correct, the marginal band on hindwing is rather broad and merging in the orange discal zone without yellow between the marginal band and the orange. The marginal band on the frontwing is broadening to the apex, in large tortoiseshell it normally gets slimmer to a the smallest point at the subapex. The very pointed shape of the hindwing is also better for scarce. Also note on the underside pics of most probably the same individual with clear pale legs. A bit of yellowish next to the black basal spot on the hindwing is not abnormal for a female but never as much as on female large tortoiseshell.

[False Apollo]

Must admit I got a bit excited about this. A Scarce Tortoiseshell was seen and photographed last week at Whitely Pastures. I have emailed the finder for the info. I think this is a first for Hampshire. Terrific find.

Regards
Mike

[Neil Hulme]

Hi Mike,
I've just seen an image of the Whitely tort. Definitely Scarce.
Best Wishes, Neil

[Jack Harrison]

We value your thoughts Neil.

Is the Scarce Tortoiseshell going to colonize parts of England? (Or has it already?)

It will be strange if it does. Many had thought that Continental Swallowtail, or Map might be the most likely to colonize (or the Large Tort to return) but I don't think anyone had ever considered Scarce Tortoiseshell until last summer.

Jack

[Neil Hulme]

Hi Jack,

For the duration of the Fritillaries for the Future project it's best I avoid discussion of topics such as this, at least in a public forum, just so as to avoid any possible confusion between my own views and those of Butterfly Conservation. However, I'll PM you.

BWs, Neil

[bugboy]

We value your thoughts Neil.

Is the Scarce Tortoiseshell going to colonize parts of England? (Or has it already?)

It will be strange if it does. Many had thought that Continental Swallowtail, or Map might be the most likely to colonize (or the Large Tort to return) but I don't think anyone had ever considered Scarce Tortoiseshell until last summer.

Jack

My thoughts on the subject (for what they're worth) are that we should first consider why Scarce Tortoiseshells aren't here already. As we know, Gorganus Swallowtails have always been regular visitors along the south coast, the Maps range has been expanding north west and without the Channel I'm sure it would already be on the UK list properly and we are part of the historical range of the Large Tortoiseshell. What is it that has kept the Scarce Tortoiseshell an eastern European species until it's population explosion last year? Nymphalis sp are strong flyers so I can't imagine there's a physical barrier so maybe a climatic one?

So will this influx change its perminant distribution to include the UK? That would depend on how many find it to our shores and whether they can find each other. I would imagine numbers on the continent closer to their natural range would be denser so perhaps it would take a few more seasons of immigrants and range expansion (if they happen) to colonise the UK. Just idle thoughts but I'll be watching the subject with great interest.

[MrSp0ck]

The numbers of Scarce Torts being seen are probably just a few of the ones that came here last summer. The number of sightings is quite high as well, so it looks like most got through the winter ok. The only handicap is if males and females can find each other this spring, if so then it will colonize if the gene pool is large enough.

The Scarce Tortoiseshell has been rapidly expanding its range the last few years, finding suitable habitat. The thing is if the parasites can expand as fast to keep the numbers down or it will spread further and faster. there are about 110 Butterfly Species just over the channel, so we should expect a few more to come over if conditions are favorable.

[monet]

The only handicap is if males and females can find each other this spring,

That's the million dollar question of course. However when you consider its amazing expansion of range on the continent ....
Here is an English translation of a paper documenting its recent expansion in Europe : http://www.phegea.org/Dagvlinders/Docum ... ersion.pdf
The original French version comes with maps such as this one which help visualise the situation. http://www.phegea.org/Dagvlinders/Docum ... ansion.pdf

[Jack Harrison]

I offer another hypothesis for the west and north-westward expansion of the Scarce Tortoiseshell.

Could the summers in its traditional range have become too hot so they are simply moving towards cooler areas?

Compare the phenomenal spread of the Collared Dove, first recorded breeding near Cromer in 1955.

First Cuckoo of year today and amazingly was a sighting. Haven't heard one yet.
Cuckoos are relatively numerous here on Mull. Too hot for them in the south these days?! (Not a good hypothesis).

Jack

[False Apollo]

After visiting Poland a couple of years ago, I was told that Scarce Tortoisehell had invaded and was starting to establish itself there. However many of these colonies are temporary, so possibly are reliant on further individuals arriving from the east in good years. The omens could be good here (if both sexes meet) in woods where the foodplant is present. From my limited experience in Poland, they can be elusive as they sail around the tops of trees. Not always easy to see, but probably easier to see after hibernation, like the Large Tortoiseshell. I wonder how many have been overlooked? Good numbers found after hibernation in the Netherlands could be excellent for the UK if the can get established there.
I wonder how far west they have travelled in the UK?
In Hungary Lepidopterists I have met get as excited with sightings of False Comma, as we do about Scarce Tortoiseshell. False Comma has moved west sporadically but has never really totally got a foothold as far as I know. It is certainly not a common butterfly in Europe where it is found, seems to be nomadic. I missed one by a day by the Danube on a recent visit.

Birds such as Little Egret are now established breeders here and currently Great White Egret has got a foothold as well. So I am optimistic with all these new spring sightings of the Scarce Tortoiseshell.

Regards
Mike

[Pete Eeles]

Hi Mike,
I've just seen an image of the Whitely tort. Definitely Scarce.
Best Wishes, Neil

The photo is on Twitter here: https://twitter.com/wildlifebcn/status/ ... 7436273664

Cheers,

- Pete

[MrSp0ck]

I see a Comma butterfly was interested in the Scarce Tortoiseshell in the picture, we had a Comma trying to pair with a Glanville last year.

[False Apollo]

The actual photo of the Whitely Pastures Scarce Tortoiseshell is on Phillip Lowe's twitter page, and very good it is too!

Regards
Mike

[Pete Eeles]

The actual photo of the Whitely Pastures Scarce Tortoiseshell is on Phillip Lowe's twitter page, and very good it is too!

Regards
Mike

Do you have a link Mike? There are almost 100 "Phillip Lowe"s on Twitter!

Cheers,

- Pete

[Vince Massimo]

Hi Pete,

Phillip Lowe's image of 21st April is here: https://twitter.com/plowe315/status/589 ... 28/photo/1
This being from Whiteley Pastures near Fareham, Hampshire.

The photo accompanying some of the sighting reports from Fowlmere, Cambridgeshire on 21st March is a library image because the butterfly was described as being very worn.
http://www.surfbirds.com/community-blog ... idgeshire/
https://twitter.com/wildlifebcn/status/ ... 7436273664

The actual sighting was by Dave Curnow and his photo is on the Cambridgeshire and Essex BC website under that date.
http://www.cambs-essex-butterflies.org. ... gs2015.php

Vince

[Pete Eeles]

Thanks for clearing things up, Vince! When folks post an image on Twitter, I wish they'd note when a library pic is being used!

Cheers,

- Pete

[False Apollo]

Sorry about not providing the link Pete, I can see Vince has done the searching. I thought UK Butterflies had re-tweeted the photo on the Twitter feed. This is a butterfly which seems to suddenly appear out of nowhere in the UK, so I can imagine Phillip's surprise when he found one at my old stomping ground at Whitely Pastures. This used to be one of Hampshire's greatest butterfly woods with some remarkable species records, the whole Botley Wood complex making for a diverse range of subtle habitat variation. Brown Hairstreak used to be there, I'm pretty sure all bar one Fritillaries were recorded. The area would be a good one for Scarce Tortoiseshell if they did breed, but as we all know, butterflies are unpredictable so this could be a one off. Whatever happened to the Large Tortoiseshells on the Isle of Wight, I wonder if they are overlooked, as the numbers were very low?

Regards
Mike
I

[Neil Hulme]

While Michael Blencowe was preparing his talk for yesterday's BC Sussex AGM, he was scanning through some older pages on the Branch website. Having swotted up on the differences between Large and Scarce Tortoiseshell, he became deeply suspicious that the butterfly labelled as a Large Tortoiseshell, seen by Stuart Cooper in Beckley Woods (East Sussex), was in fact a Scarce Tortoiseshell!

He rang me to ask for a second opinion and as I brought the old image up I nearly fell off my perch! The date .... 12th March 2014! This implies that the butterfly had overwintered in East Sussex and must have arrived in the UK during the summer of 2013.

Although the species was undergoing a further phase in its rapid range expansion at this time, spreading northwards and westwards in southern Finland, and westwards through southern Sweden (Manil & Cuvelier, 2014; Fox et al, 2015), this new Sussex record remains well ahead of (observed) incursions into Norway, Denmark, Germany, Netherlands and Belgium, during July 2014.

Unless the history of the woodpile on Shetland, which contained a xanthomelas (November 2013), can be accurately determined, this places the Beckley Woods specimen ahead of the post-1953 pack. A great bit of detective work by Mr Blencowe. The cat has been put firmly amongst the pigeons!

Scarce Tortoiseshell, Stuart Cooper, Beckley Woods 12th March 2014

[Jack Harrison]

You have thrown my memories into chaos. I had to look up the date but know it was spring 1948 and FA Cup Final day. Football records show that date to be 24th April.

I lived in north east Suffolk (now in Norfolk) near Gorleston, Great Yarmouth. Yarmouth has always been in Norfolk and was once the home of the legendary F.W. Frowhawk. Gorleston was the other side of the river and was in Suffolk then.

On 24th April 1948 I saw and failed to catch, a “large” Tortoiseshell. I was nine years old at the time. That was my one-and-only sighting of a “large” Tortoiseshell and I have always assumed it was the Large Tortoiseshell, polychloros. But now I have to wonder: might it have been xanthomelas? Unlikely but not impossible. Oh dear.

This old man is now horribly confused!

Jack

[Padfield]

It goes without saying we will never know, Jack (why do people like me insist on saying what goes without saying?). But thanks to the predilection of old-time lepsters for taking specimens, we have the evidence that until very recently, most large, tawny tortoiseshells seen in the UK were polychloros. That certainly doesn't mean no xanthomelas passed unnoticed, especially as in the early years of the 20th century large tortoiseshell was not regarded as a notable butterfly in the east of England; but my feeling is that something new is happening here. Given that the likes of Ford et al were well aware of the existence of xanthomelas it seems improbable it was arriving in significant numbers.

The Blencowe specimen strikes me as highly probably xanthomelas, not least because of the light colour evident on the left 'foreleg' (technically, middle leg). I religiously checked every Swiss and Italian large tortoiseshell I saw in 2015, and spent many hours in the spring and summer in the UK looking for them in likely spots. To date, I've still never seen xanthomelas (not counting a youthful sighting in Gibraltar, which I expunged in a mid-life purge). But having personally witnessed and documented the arrival of Argynnis pandora in Switzerland as a breeding species in the last few years I know species do sometimes undergo important changes in distribution. It's very exciting if xanthomelas is experimenting with north-western Europe.

Guy