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.

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. 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