West of Our Border

The Suffolk Argus

West of Our Border

Mervyn Crawford In recent years the close proximity of the Chalkhill Blue and Marbled White to the Suffolk border at the Devil’s Dyke has prompted rather optimistic searches in neighbouring tetrads in the hope that westerly winds might lead to a few stray insects crossing the border. However, so far the county boundary has proved something of an invisible barrier in spite of the occasional sighting of a Marbled White in places like Fordham, Burwell and Soham. Rather more frustrating is the regular occurrence at nearby Cambridgeshire sites of some species we are in danger of losing from Suffolk. I turned up an old Argus article that I wrote back in 1999 on ‘Eggars, Lackeys and Emperors’ . It came as something of a shock to realise that in the intervening twelve years I had hardly come across any of the early stages of the species I had then described as being ‘easy to find’ . So I set out this year to see if I had lost my knack of successfully searching the hedgerows or whether numbers had indeed suffered serious declines. I was rewarded by finding a few larvae of most species around Mildenhall with the exception of the Pale Eggar, Lackey and the Lappet. This latter species causes real concern as it is a most handsome and showy insect in its stages. With a typical schoolboy ’s inquisitiveness, in the late fifties I used to find the huge brown larvae in the spring on almost any suitable stretch of thorn hedgerow. My father would irritate me as he recounted dislodging them with sticks when they became something of a pest in the orchards at Brome Hall where he was a gardener just before the last war. Up until writing my article I could discover them in far lesser numbers by beating in the autumn before they hibernated. With a daughter who has recently moved to Wicken, I am sometimes called upon to walk her small Cairn Terrier. There are one or two very pleasant footpaths between Wicken and Soham and on one of these I was just looking down at the number of green damsons that had presumably dropped early because of the very dry spring. Some large caterpillar droppings were also very evident and my heart skipped the proverbial beat, because to me this could only mean one thing! Needless to say, within minutes I had found three fully grown Lappet larvae as big as medium cigars. I was compelled to return later in the day, this time with my camera. A day or two later two more were found just on the Cambridgeshire side of Isleham marina on a riverside Sallow bush.

From my garden in Mildenhall, when lopping my tall Leylandii hedges, I can see the Soham water tower about six miles away as the crow flies. So they really are that close! Even more of a heartache has been the single-species survey done on the Wall butterfly this year. For the past two seasons I have drawn a complete blank in those fenland areas to the north-west of Mildenhall where even as recently as eight years ago it was numerous, and I have to sadly agree with our County Recorder’s emailed comment that we appear to be monitoring a sudden and catastrophic decline of this species in Suffolk. It is almost

hurtful to recall when this was a common species everywhere, especially on roadside verges and even in town gardens where it would accompany Vanessids on Buddleia, Michaelmas Daisies and Sedum. It was also the first ‘Brown’ to appear in the spring before Speckled Woods spread to Suffolk. However, on the p r e v i o u s l y m e n t i o n e d walk some six weeks later, I r e c o r d e d three Walls. The strange thing is that here the best description of the habitat would be ‘arable field margins’ , something from which it has long been virtually extinct in Suffolk. It is still to be found in smallish numbers in E. Cambs, and, thankfully it is still a species of all habitats just across the Channel into France.

I am just old enough to recall the similar swift and unexplained demise of the Large Tortoiseshell in the late Forties. The plight of the Wall is worryingly similar. Obviously, the Walls decline is less marked elsewhere in the UK and it could be one of those species that is expanding its range northwards. All of which is small comfort to those of us who wish to remain living in our lovely county of Suffolk.

Illustrations by Mervyn Crawford

Butterflies name change

From Richard Fox, BC Survey Manager We are lucky in the UK to have longestablished and stable vernacular names for butterflies. As a result, our day to day interest in butterflies is not complicated by taxonomic rearrangements and changes in scientific nomenclature. Nevertheless, scientific names are important and there has been a recent, comprehensive revision of the taxonomy of European butterflies, carried out by the Butterfly Conservation Europe Taxonomy Group. This has been adopted by Butterfly Conservation.

Only six changes, all at genus level, affect species that breed regularly in the UK. Three species are placed into different genera (Purple Hairstreak becomes Favonius quercus, Large Blue Phengaris arion and Peacock Aglais io), while the other three revert to genera that will be familiar already (Silver-studded Blue moves back to Plebejus argus, while Brown Argus and Northern Brown Argus revert to the genus Aricia). An appeal has been lodged against the change of genus for Large Blue, but for now the new taxonomy is correct.

The listing is available on the Fauna Europaea website www.faunaeur.org.

This report, which covers changes in the abundance and distribution of butterflies over the last 10 years, is now almost ready for printing. BC plans to launch with a press release by early December.