Butterflies & Moths

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Butterfly & Moth Details

Project Hairstreak

The background

White-letter Hairstreak
White-letter Hairstreak
By Ian Kirk from Broadstone, Dorset, CC BY 2.0, Link

If one were to ask a random sample of local people to spontaneously name a few butterflies from this area, I imagine that such familiar species as the Red Admiral, Peacock, Small Tortoiseshell, "Cabbage White", and maybe Brimstone, Comma, Speckled Wood and Holly Blue would be near the top of the list. I doubt however that many would come up with the White-letter Hairstreak, a pretty if not strikingly beautiful medium-sized butterfly that gets its name from the large "W" shaped white line on the underside. Hence its Latin name of Satyrium w-album. It is not a common butterfly, in fact it could easily become on the "endangered" list if not properly cared for.

White-letter Hairstreak larva
White-letter Hairstreak larva
By Ptelea - Own work, CC BY-SA 4.0, Link

In my experience the White –letter hairstreak is unusual in that having found a location where it exists it is possibly easier to discover the larva than it is the adult. The butterfly frequents Elm, on which the larva feeds, and with sharp eyes or a pair of binoculars the adults may occasionally be seen flitting in and out of the upper branches, often resting for lengthy periods. Hence they are unobtrusive and difficult to spot let alone identify with any certainty. In contrast the bright green woodlouse-shaped larvae can be found relatively easily by simply lifting up the lower branches and holding them against the light, when their silhouettes will easily be spotted despite being exactly the same colour as the leaf. In the space of about half an hour I once collected 16 in this way in from a location I knew at Sunninghill near Ascot and successfully reared them through to adults, very satisfying.

But why my sudden recent interest in this butterfly, and what has it to do with Earley? Well, back in the 1960s I and a couple of like-minded friends (Terry Babbage of Mill Lane and Richard Beard of Radstock Lane, both fanatical lepidopterists), used to spend the best part of our summers looking for butterflies in the daytime and moths at night. The latter was frequently done around the mercury-vapour street lights of the time which attracted moths in abundance but which sometimes resulted in a visit from a local police constable. These visits, I'm pleased to say, always ended amicably and with the various policemen taking quite an interest in what we had caught! But I digress. The salient point is that over a period of many years we built up a considerable knowledge of the Lepidoptera of this area, in particular the woods and fields around Maiden Erlegh. If the White-letter Hairstreak was present we would surely have encountered it at some point yet we never did. Dutch Elm disease was beginning to take a heavy toll, the Elm trees were dying and the outlook for the butterfly seemed bleak indeed. And all the while there was the threat of losing our precious woodland to developers, a hideous proposal that was awful to contemplate. Thankfully, due to the strenuous efforts of certain enlightened and far--sighted individuals this never came to fruition and eventually resulted in the priceless nature reserve that we enjoy today.

Elm-bark beetle Elm-bark beetle
By Se90-Own work
CC BY-SA 3.0
Link Fdcgoeul [GFDL or CC BY 3.0],
from Wikimedia Commons

After a few years both Terry and Richard moved away, Terry to Stratford on Avon and Richard to Vancouver, Canada. Terry and I continued to meet up for the occasional butterfly expedition, and still do, but Richard and I lost contact after a few years, although I'd heard he was doing great work in butterfly conservation in his new life. Fast forward several decades to about 2014. On a bright breezy morning, approaching the bridge that crosses the lake outlet I was very surprised to see a White-letter Hairstreak fly down and settle for a few seconds on the wooden planking, the first I had ever seen or heard of in our area. At the time I did not attach too much significance to this event as freak sightings do occur from time to time- for example the Purple Emperor that was seen and photographed on a lawn in Instow Road in June this year (2018). Certain butterfly species can be remarkable travellers when necessary! However, the following year there was another definite sighting from an utterly reliable source, followed by a "probable" sighting from a different but equally reliable source. All these were in the same area near the bridge. Perhaps the White-letter Hairstreak was trying to gain a foothold in our nature reserve? An attractive thought indeed! The likelihood of this was compounded by the discovery that a number of small stunted elms were present in the immediate vicinity, although these were invariably succumbing to Dutch Elm disease when only a few metres tall. Unfortunately these do not produce seed and can only reproduce by means of suckers which are of course genetically identical to the non-resistant parent tree. But maybe that is just enough to sustain at least a small, albeit precarious population of White-letter Hairstreaks? At the time of writing (Autumn 2018) we simply don't know.

The proposal

And so to May of the present year. Imagine my amazement when I was forwarded an email from the "enquiries" section of the Earley Environmental Group website asking that if I should happen to read this could I please make contact with my old friend Mr Richard Beard in Vancouver, Canada? Naturally I did so and thus started a flurry of fairly lengthy correspondence- we had a lot of catching up to do! Among much other news Richard explained that his father, Colin, who had played a pivotal role in saving the woodland and lake from development had sadly passed away last year and that he (Richard) had been in England recently to attend the memorial service with his brother and sister. Whilst here they had paid a visit to their old haunts around Maiden Erlegh Nature Reserve and had been mightily impressed by the amount and quality of the conservation work that has so obviously been put in by the Park Rangers, the Wednesday Volunteers of the Earley Environmental Group and no doubt other interested individuals as well. Bearing in mind that this had been made possible in the first place by the sterling efforts of Colin and a few others they had decided that they would like to make a contribution to the Reserve that would be in keeping with his wishes and interests. Could I suggest something? Something butterfly-related perhaps? I said I would try and went away and had a Big Think.

Several ideas came to mind but before coming to a definite decision I needed to discuss the matter with the Park Ranger, Grahame Hawker. Accordingly we arranged to talk things over on the following Wednesday morning at the regular meeting of the Wednesday Volunteers.

I should think it took us all of 2 minutes to agree a firm proposal that I could put to Richard's family. We would try to obtain and plant some elm saplings of a cultivar that was resistant to Dutch Elm disease. Grahame knew of a potential supplier of these who, by an amazing stroke of good fortune, also happened to be Butterfly Conservation's "species champion" for the White Letter Hairstreak. This person, Peter Cuss, would obviously know a great deal about the ecology of the species and could give us much sound advice. Accordingly, Grahame contacted Peter who said he would be more than happy to fall in with our proposal, give us the benefit of his wide knowledge and supply us with some trees in exchange for a financial contribution to the Butterfly Conservation charity. This was exactly the sort of answer we were hoping for. I therefore contacted Richard with our proposal who in turn outlined it to his family who were very happy with the idea and so the deal was struck. Butterfly Conservation duly received a handsome donation and we received our trees.

Elm tree Ulmus minor subsp. minor
at East Coker, UK

By Ptelea [CC BY-SA 3.0],
from Wikimedia Commons

The next step was to establish where and when the trees would be planted. Peter, Grahame and I therefore spent some time walking around the Reserve looking for suitable spots and found one which seems ideal. However, bearing in mind what has happened to some of the trees in the Community Orchard I hope you will understand if I do not pinpoint the exact location until they are firmly established and growing well. The site was prepared by the Wednesday Volunteers and other interested parties who will also ensure that the trees are cared for and nurtured while they become established. An important point is that the trees are of a cultivar that produces seedlings readily, thereby increasing the chances of the species adapting to local and changing conditions. The saplings were delivered on October 22nd and the last-minute site preparation and actual planting took place on the beautiful Autumn morning of the 24th by a team of some thirteen enthusiastic volunteers. Obviously the project will not come to full fruition until many years hence but that's conservation! Fully mature Elms, surely one of the most beautiful and iconic sights of the English countryside but now so seldom seen will hopefully once again become an outstanding feature of our Nature Reserve. And if the White-letter Hairstreak finds things to its liking, and I can think of no reason why it shouldn't, that really would be the icing on the cake. A suitable memorial indeed to the far-sighted Colin Beard and his colleagues who saved the Reserve in the first place and to those who have developed and nurtured it ever since.

Alan Broodbank
October 2018

This article first apeared in the magazine of the Maiden Erlegh Residents Association, Autumn 2018.

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