www.ukbutterflies.co.uk

Towards the end of Roger Gibbon's excellent recent zoom presentation on French species with a UK connection, there was discussion regarding the best place to find distribution data on European species. Roger mentioned the French maps by Lafranchis, available at diatheo.weebly.com, which I agree has the best, most up-to-date and detailed maps of French butterflies, by a long way, without delving into the recent regional atlases of France such at the excellent PACA atlas, also mentioned by Roger.

Mention was made (possibly by Bill Raymond?) of the LepiDiv project - which presents online distribution maps of most of the European butterfly fauna.

I hadn't visited this site before, but have had a quick look around and it is certainly interesting and worth a visit! Inevitably there will be errors and a lack of fine detail when attempting to create a pan-European distribution map for any species, but most of the maps I have looked at so far (and I should stress that I have only looked at a few dozen) seem to give a fair impression of species range, although the date categories mean that some of the data are quite old. Records are categorised as pre-1950(red dots), 1951-1980(yellow), and post-1980(green).

However, the British distribution maps of two species that I viewed immediately jumped out at me as being rather over-optimistic! Namely, the Small Blue and the Scotch Argus, copied in below from the website.

Would be interested in any one else's comments before I submit any feedback to the LepiDiv website.

Thanks Pete. Personally, I use: Kudrna, O. (2019) Distribution of Butterflies and Skippers in Europe. Czech Butterfly Conservation Society. However, this is not a free resource: https://www.nhbs.com/distribution-of-bu ... urope-book

Given the sample shown, High Brown Fritillary also seems to have an optimistic coverage!

Cheers,

- Pete

Agreed Pete! If only some of these distribution maps were true...

The one below for Large Chequered Skipper is particularly intriguing: According to the LepiDiv website, some of the data is still based on Kudrna's "Distribution Atlas of European Butterflies" (2002).
UK records from 1690-1999 are acknowledged on the LepiDiv website as originating from the BNM, courtesy of BC and the BRC, supplied via the NBN gateway (I suspect this may be where errors have crept in).

The LepiDiv website is an excellent idea, and has some really useful maps. It is a shame that the UK data seem not to have been checked before inclusion, and it does make you wonder if there are similar errors in the data from other countries.

Wouldn't it be nice to see morpheus flying from Hampshire up through Oxfordshire, Leicestershire and in Cumbria etc?!

There's something weird going on there, given the straight line across England! It could be the records from Jersey being mismapped several times!

Cheers,

- Pete

These pan-European distribution maps may be useful as a general guide, but they can be extremely inaccurate at a local level, which I suppose isn't surprising when a single green spot denoting the presence of a species is a similar size to a capital city!!

Following on from Pete E's comments regarding Kudrna (sadly no longer with us - RIP), that too contains many highly over-optimistic distribution charts. I will use High Brown Fritillary as an example, although you will see that LepiDiv's for the same species is even more inaccurate for the UK (one would be forgiven for believing that this butterfly was common and widespread in the UK):
I agree with Pete S that Lafranchis' charts provide a much greater degree of accuracy (albeit for a single country, France). You simply can't replicate the level of local detail in an individual country with a map showing the entire continent. For example, look at all the small pockets of territory occupied by High Brown Fritillary in Lafranchis' work:
For those species that are highly localised, he uses departmental scale, rather than national, for instance in this map for False Mnestra Ringlet, which is only found in the far SE of France, near the Italian border:
That level of detail simply isn't possible to portray in a continental distribution map.

I’m not sure what methodology was used in producing the LepiDiv maps, but it has to be said that if they can get morpheus that wrong (maybe they dreamt it – ha-ha) one wonders how much else is wrong.

As David says, the Lafranchis maps give a much more accurate picture of the distributions in France, as the adippe map shows. There is quite a lot of data collected in/by each of the French départements and it seems Lafranchis has access to this, so he can show the full picture country-wide.

The conundrum is how to get large numbers of people involved in recording (the Big Butterfly Count has been a fantastic success in this regard) while at the same time ensuring that records from less experienced observers is accurate.

The recent CEN-PACA Atlas had some 680,000 records at its disposal. What they did, and it may be normal practice, was to appoint a validation committee to look at all records which did not appear to be in the right place, and ask the record donor if they had a photo or some other form of confirmation. I was on the committee and questioned only two or three records, one in particular I was sure could not be right. I think CEN worked on the sensible principle that that it was better to leave out a dubious record than publish something that might be misleading.

In truth, some highly localised and sedentary species may occur in a small region in a number of very small disparate communities, and not necessarily in between, so 10 km squares really doesn’t tell you much. Not that we want to advertise too widely where to find the rare and iconic species.

Roger

David M wrote: ↑Wed Apr 07, 2021 10:00 am These pan-European distribution maps may be useful as a general guide, but they can be extremely inaccurate at a local level, which I suppose isn't surprising when a single green spot denoting the presence of a species is a similar size to a capital city!!

Indeed David, that's putting it mildly!

I am particularly surprised by the apparently aquatic example of the High Brown Fritillary - the green dot in Kudrna's map half-way between the Isle of Wight and Cherbourg - do you suppose it was an immigrant and landed on a cruise ship perhaps?

It's easy to be critical, but it does make me wonder what degree of proof-reading goes on before releasing such publications.

On that note, as I have a publication of my own coming out very shortly, I shall shut up and duck down behind my parapet!

There are plenty of 'oceanic' sightings if one trawls through the charts, Pete.

Just shows the impossibility of creating accurate distribution maps at such a large scale.

Surprisingly perhaps, Water Ringlet is entirely restricted to dry land!!

I can't disagree with anything that is said in the above posts. Those are my experiences too.

I guess the only thing I'd add is that, whilst we use the various distribution maps as a guide to what might be seen in an area, or to decide where to travel to, to try to find a target species; there is nothing better than finding a species in an unexpected place.

One of the highlights of my European butterfly experiences was finding a colony of Violet Copper's in a part of Switzerland where they'd not been spotted for over 20 years, over 40 miles from the nearest known colony. The Swiss distribution maps are excellent, (see this website: http://lepus.unine.ch/carto/), and I can now proudly say that my Violet Copper sighting is now a blob on the latest map, as well as another nearby blob that was created a year later by someone else, following up on my own sighting.

If this sort of thing can be done in Switzerland, where there are so many spotters and distribution mapping is so good, just imagine what new records and discoveries are possible in the much less well covered areas in the Balkans, eastern Europe, and even places like Italy.

Makes you want to fly out to Europe right now to get spotting and discovering.....!

selbypaul wrote: ↑Sat Apr 10, 2021 7:24 am there is nothing better than finding a species in an unexpected place.

Completely agree Paul - it is always a great thrill to locate species, particularly rarities such as Violet Copper, in new areas, and to add dots to maps!

I have been fortunate to do just that with a few special butterflies over the years, most memorably with such species as Poplar Admiral, American Painted Lady, Ripart's Anomalous Blue etc.

There are certainly many discoveries still waiting to be made in Europe - if only we could get there...fingers crossed it won't be too long before it is possible to travel once again!

Concur with the above. Butterflying in Europe can be full of surprises and most areas are far more 'unrecorded' than in the UK.

Plenty of opportunities to find species in places where they haven't been known to officially occur, and who knows, if you are stumbling along the coastal strip in the Cote d'Azur, you could even reinstate Pygmy Skipper as an extant French species!!

if you are stumbling along the coastal strip in the Cote d'Azur, you could even reinstate Pygmy Skipper as an extant French species!!

Good luck with that! I have spent many hours in rocky littoral areas in Provence without any success. Tim Cowles came down one year and we spent a day in an area he had researched. No joy, and I did plan to try that area again in September (main flight period) but that has not been possible for the past couple of years. Maybe this year?

I was asked by Stéphane Bence of CEN-PACA to check out a reported sighting (no photo) near Cagnes-sur-Mer but found nothing that could have been Pygmy Skipper. A few years ago we searched an area suggested by Tristan Lafranchis as a possible (historical) site, but no joy. It could be hanging on in some small outpost, but I think it is now long odds against.

On the subject of unexpected findings, when we first went to Var in spring/summer 2006 I checked out sites that I had previously researched (isn’t Google Earth wonderful?) for possible Provence Hairstreak, erstwhile only known from very few locations in France. Surprise, surprise, I found it in another four entirely separate locations, one quite far removed in the east of Var. It is a very sedentary species and quite hard to spot in flight and it generally only flies across bare earth, so it had probably gone unnoticed by the few people who were recording in that region. Since then, CEN-PACA organise a research group to explore a different potential location in the first week of April each year. It gets up to 50 volunteers to spend a day searching and, guess what, they usually find it. To me, that’s good news (it is not rare) and bad news (sort of, my finds weren’t that exceptional).

One of those sightings was in April 2011 with Rogerdodge, Kip and Nick B at a location in central Var I knew well. Nick said there’s another of those green hairstreaks (we had just seen them the day before in a known location) and, true enough, another previously-unknown Provence Hairstreak location was found.

I have had similar experiences in eastern France with the rare and highly-localised Violet Copper, and Pete Smith’s travels to the same region flagged up a number of previously-unknown locations.

Even places that I had visited many times before still throw up surprises. On a tour to everyone’s favourite spot in the Mercantour, in 2014 I pointed out what I thought was a (common) Southern White Admiral to the group and had to immediately revise that to the rare Poplar Admiral – which I had never even thought might fly there in the 15 years I had been visiting that site.

Roger

Some really good examples their Roger. It absolutely is worth studying ever sighting you see, just in case!

Roger Gibbons wrote: ↑Sun Apr 11, 2021 9:57 am...I have spent many hours in rocky littoral areas in Provence without any success. Tim Cowles came down one year and we spent a day in an area he had researched. No joy, and I did plan to try that area again in September (main flight period) but that has not been possible for the past couple of years. Maybe this year?

I was asked by Stéphane Bence of CEN-PACA to check out a reported sighting (no photo) near Cagnes-sur-Mer but found nothing that could have been Pygmy Skipper. A few years ago we searched an area suggested by Tristan Lafranchis as a possible (historical) site, but no joy. It could be hanging on in some small outpost, but I think it is now long odds against.

Sadly, I think you're right, Roger, as much time has passed since the last definite sightings. That said, a tiny, drab butterfly that flies extremely fast could go under the radar far more easily than a larger, more colourful one with a more visible flight pattern.

We live in hope.