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COMMON BLUE BUTTERFLIES AT SIZEWELL There was a tremendous storm during the night of August 14th 1993, with spectacular lightning, unbelievable thunder and torrential rain. So how could fragile butterflies possibly survive? The next day we went for a stroll along the dunes at Sizewell at about 4.30pm, on a sunny and wannish afternoon, not expecting to see many butterflies, so did n't bother to take the camera. At first there were very few, but as we went along the path between the wire fences on the Sizewell B site we began to see Common Blues. The site on either side of the path has been re-seeded with grass and wild flowers. We were surprised to see quite a few Blues along the path but were quite unprepared for what followed.
For those of you fortunate enough to have been able to enjoy up to 40 species of butterflies in Suffolk as recently as the l 950's, it must be difficult to accept that a good year's watching in the 1990's will only yield a maximum of 31 - and this with no small amount of hard work and luck, together with the inclusion of the three non wintering migrants, (Red Admiral, Painted Lady and Clouded Yellow). If you were butterfly watching in 1900, you could have seen a further 6 species; early in the century before, another 7. Yes, we have lost 21 species in Suffolk since the beginning of the 19th century and have the dubious honour of heading the national extinction list for the combined 19th and 20th centuries. How this has come about is open to much debate, but I am sure that no-one would disagree that changes in land use must be central to the cause. The effects of these changes were swift and dramatic in the years following the last war. Little harmful change in land management was evident until the 19th century when we began to notice the loss of some of the butterflies that used to thrive in the county. At this time, coppicing began to decline and game preservation developed, affecting Suffolk's woodland species. However, the 19th century was also the peak period in this area for the digging of chalk pits and quarries -favoured by Brown Argus and Dingy Skipper as well as the more common grassland species- although this did not stop the disappearance of most of our chalk downland butterflies before 1900. In more recent years many of these man-made habitats have also gone. The parallel decline of the working horse and the general move away from livestock to intensive arable farming led to a scarcity of wet meadows and pastures and the Marsh Fritillary became a casualty as long ago as 1904. The reclamation of large areas of the Brecks for arable during the rest of the century and the advent of scientific agricultural methods had a marked effect on heathland species. The Silver-studded Blue disappeared from the Brecks completely. Intensive arable fanning was accompanied by a massive afforestation programme during the 1940's and I 950's and the methods used contributed heavily to the demise of our woodland butterflies. Add to this the affects of myxomatosis on grassland species and the possible influence of subtle climatic change, and it is not difficult to understand how butterflies have declined to today's levels. 1.1
tm. SI IFFOLK ARGUS Vu/ 1
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At the far end of the pathway the dunes opened out, with a wire fence on the land side only. On either side of the fence were tall drying grasses and flowers - Ragwort, Bird's-foot-trefoil, Sheep's-bit Scabious, Harebells and Clover.The grass on the dunes was short, growing taller again by the sea, with more flowers on the little hillocks. We realised that there were scores of Blues, male and female, wherever we looked, resting on the grasses or nectaring on the flowers. We had never seen so many in one place. Crossing to the shingly beach we saw many clumps of Sea Holly and Homed Poppies, and these too seemed to be alive with blue butterflies, which flew up in clouds as we approached. It was an amazing sight. THI~SUFFOLK ARGUS Vo! I
By about 5.30 pm., as we began the return walk, we realised that the Blues were beginning to home in on the grasses, preparing to roost for the night. Every few feet there were clumps of grass with Blues in tens, twenties, up to fifties, roosting head down on the taller grasses.They would fly up as we passed and then settle down again. We reckon that in a half-mile stretch there must have been between one and two thousand Common Blue butterflies. It was a marvellous experience. We also saw one or two Meadow Browns, a few Gatekeepers, plenty of Large and Small Whites, a few Small Tortoiseshells, about fifteen bright Small Coppers and at least thirty Graylings, mainly on the Sea Holly clumps. Next year we hope to lead a walk along the Sizewell dunes, hoping for a repeat performance from the Common Blues.
Michael and Jenny Kelsey
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