Fritillary colonies reappearing

[A_T]

http://shropshire.gov.uk/news/2012/06/r ... ellesmere/

Wildlife enthusiasts were attending a free butterfly course, run in conjunction with Butterfly Conservation, when they unexpectedly stumbled across a Small Pearl-bordered Fritillary (Boloria selene).

The discovery was made at Ellesmere Moors, where habitat restoration work has recently been undertaken through the LEADER-funded community project. This beautiful species had not been seen around The Mere for 20 years and it was thought to have been lost from the area.

I was interested to see this article about Small Pearl-Bordered Fritillaries being rediscovered at a site at Ellesmere, Shropshire. I wondered why it had not been seen for 20 years. It seems possible that simply noone noticed any - or that maybe once the habitat had been cleared someone introduced some larvae. Unlikely that is was colonised from elsewhere I would have thought as there are no other SPBF sites less than several miles away - unless there is another one nearby unrecorded.

Would be interested to hear people's thoughts and reflections on this.

[essexbuzzard]

An introduction,i would have thought. It would be surprising if a colony in the area had gone unnoticed.
A natural recolonisation also seems unlikely if there are no near colonies,as this is mostly a not very mobile species. An exception to this is in Cornwall,where they range quite widely around the coast,and also in the Scottish Highlands,where adults fly up and down the mountainsides.
I personally have no problem with such introductions,provided the habitat can be maintained. Many isolated sites would never be colonised naturally.

[Goldie M]

Could the Bolaria Selene I saw in Gaits Barrow possibly make it's way to Shropshire do you think Goldie

[David M]

Could the Bolaria Selene I saw in Gaits Barrow possibly make it's way to Shropshire do you think Goldie

Only if it took a taxi, Goldie.

[Goldie M]

Hi! David, sorry about being so flippant They say severe weather conditions can cause this uncommon change in SPBF,
We've had two very cold winters before this last one, I suppose this could have affected them. If however they've been given a special name like they have "Bolaria Selene", this means they are a species in their own right
The fact no one as seen them before for a long time doesn't mean they've not been there. It makes me wonder if this is so.

When I stumbled on to the ones I saw, I thought at first they were just White butterflies it was only on close contact with them ( they landed right in front of me) that I became aware they were differant, this and the fact a man was there with Binoculars and pointed out they looked differant, other wise I wouldn't have given them a second look I 'd have gone on filming the SPBF not what I thought was a WB. Could this be what's happened in the past I wonder. I know one things for certain now I will look at every White Butterfly, more so where the SPBF are known to be from the end of May to the beginning of August just in case. Goldie

[David M]

The fact no one as seen them before for a long time doesn't mean they've not been there. It makes me wonder if this is so.

I sometimes wonder about that regarding English Chequered Skippers.

[Matsukaze]

SPBF cannot wander very far, as its failure to colonise Ireland indicates - there must be an abundance of suitable habitat there. It is a reasonably common butterfly in the wilder parts of Shropshire, but those are some way from Ellesmere.

[Padfield]

Goldie: I'm not sure if I completely understood you, so please forgive me if I'm saying what you already knew! The (fantastic) white small pearl-bordered fritillaries you saw were the same species as all British small pearl-bordered fritillaries: 'Boloria selene' is the name given to small pearl-bordered fritillaries in general. Yours were a rare aberrant form of this species. I suppose, in principle, this form could appear in any population, though it's so rare I doubt it has actually been observed in every population. Near me, all small pearl-bordered fritillaries are so rare I get excited whenever I see one - and if I saw a white one I would probably have to ask my headmaster for sick leave ...

Guy

[Goldie M]

Hi! Padfield, I'm totally ignorant of the latin name for this species( It is Latin isn't it ) I think I'll go to my local libary and start reading about Butterflies I know the name of the White one is Bolaris etc I just thought they'd called it that because it was so rare. I must admit my only interest in Butterflies is because they are so beautiful and I love taking shots of them. I've learnt more about them since jioning UKB than I ever knew before so please for give my ignorance.
I know all their names but not the Latin ones which, if I admit it ,I'm not really bothered about. I'm no expert but I do like to follow what people say about them on UKB It's only then if I don't understand I'll look it up.
Everybody seems an expert on UKB So when I put my foot in it so to speak it's very obvious I'm not It's Ironic really that I saw these lovely Butterflies and knew nothing about them except the fact they were differant, I'll certainly be going back to Gaits Barrow early June next year . Goldie

[A_T]

SPBF cannot wander very far, as its failure to colonise Ireland indicates - there must be an abundance of suitable habitat there. It is a reasonably common butterfly in the wilder parts of Shropshire, but those are some way from Ellesmere.

Yes I would think colonisation is out of the question - the colonies in the Oswestry Hills are some 10 miles plus away. Most likely is a reintroduction once the clearing had been done though I still think they might have been always there but have only come to notice now this particular site has received some attention - I've never been there so don't know the condition of the site before and after clearing.

Looking forward to Spring and going to investigate.

[Essex Bertie]

In Argyll this year, we saw SPBF in lots of isolated clearings. They seem to be able to exist at very low density all over the landscape and need far less ‘looking after’ than Pearl-bordered. Based on my few days experience of the species, I wouldn’t rule out anything natural in this instance. And do we know whether this is a ‘colonisation’ or simply a wandering male that has decided to try his luck elsewhere? All eyes on Ellesmere next year!

[Cotswold Cockney]

Whilst the Irish Sea may be an almost impassible barrier, most of the Fritillaries are strong flyers. Even the Heath and Glanville. The Pearl and Small Pearl BFs most certainly are. Even fragile butterflies like the Holly Blue and Wood white can cover relatively long distances over a period of a few days as I've observed occasionally during my lifetime of observing butterflies. I have even seen a strong flying Chalkhill Blue female in the middle of a Purple Emperor woodland many miles from their usual Chalk and Limestone downlands. The Chalkhill Blue is a more powerful flyer than the Large Blue.

I strongly suspect that in every brood of butterflies, there's always a few which will be born programmed and equipped to leave their usual site and literally seek out fresh pastures. It is the random way of nature to provide a wider chance of survival of any species. Even slow moving things like slugs and snails can cover a distance over a period.

My numerous own observations sometimes throw up a species in an area which I had known for years and never before seen it there and suspect it had been a recent colonisation. Then sometime later, often years later, I find out that it was there a hundred years before i was born. There again, I know of large woods where I have frequently visited for over fifty years and then for the first time a few years ago, see a few Wood Whites there. I do know of strong Wood White colonies but they are 20-30 miles away. So how do they get there? Not an introduction, in those fifty years I've never seen another soul there in that remote, little known woodland except the occasional gamekeeper.

Back in the 1960-70s, my occupation involved much travel about England and Wales from Morecambe across the country southwards. i would often take a route which passed new territory for me and would stop occasionally eat my packed lunches there and explore. On more than one occasion, I spotted a Wood White slowly working its way along a hedgerow on intensely agricultural farmland for miles without stopping, far removed from any woodland or even less suitable habitat. Making slow but, steady progress.

Up on the nearby Cotswold Hills both Small and Pearl BFs survive in scattered low density colonies, one or two within three miles of where I have lived for forty years. I can see two such woods from my bedroom window where I have known them since the early 1950s.

Over on the other side of the River Severn, there are many more suitable Woodlands and again, my favourite wood had very large populations of both back in the 1950-60s. Far more numerous than I've ever seen before or since anywhere. Changed woodland management has reduced their numbers considerably and they tick over at very thin densities. Beautiful woods deeper into the Forest of Dean and its outlying satellite woodlands have always had thin populations. Maybe large populations but I've not seen them, only singles or a few. I have seen the occasional single PBF flying fast and strongly through a woodland ride, not stopping but carrying on out of the wood far away over unsuitable agricultural land as though migrating. They can really shift when in this flight mode.

So, just because something may not be seen there despite many visits by an experienced observer, doesn't prove they are not there. There again the sudden appearance of a species not seen there ever before over decades could be simple natural colonisation.

Yes, when in a determined mode, even very fragile butterflies like Holly Blues and Wood Whites can cover long distances quickly and relatively easily when conditions and circumstances allow.

[dave brown]

We should also not forgot the effects of wind on insect migration. Whilst many insects, such as moths, are not built for long migration, they can actually achieve this given the right conditions including wind force and direction. This can be observed at migration headlands such as Dungeness when migrant moths and dragonflies from the continent are trapped followng a night of the right conditions. They obviously need the built in urge to migrate in the first place but a favourable wind means they can, and do, turn up almost anywhere.

[Matsukaze]

Hi Dave,

The Glanville Fritillary breeds at Cap Gris Nez which is within sight of Kent (if not perhaps Dungeness). I found a chenille there this spring; some locals found me lying flat on the path trying to photograph it and I attempted to explain to them that it was extremely rare in England. We know from its occasional crossings of the Solent that sometimes it goes out over water so if there is a period of south-easterly winds at the right time of year you never know...

[Essex Bertie]

Interesting observations on the migratory capabilities of the Wood White, Cotswold Cockney. The last natural sighting of this species in Essex was in 1976, also the year of the final extinction of the nearest colony in Hertfordshire (nearly 20 miles away). I don't think that this is the case with the Ellesmere SPBF, but I do wonder whether a singleton of a rare species can occasionally be a bad sign. i.e. the last male of a colony wandering miles to find a mate.

Rob