Tuesday 23 July 2013

A flutter of excitement

A brief flurry of excitement the other week. Returning from a butterfly survey in Baluain Wood, above the castle a flighty fritillary butterfly was sighted. After a short but mad dash, waving the butterfly net wildly about to apprehend the fast flying and elusive insect, it was caught. A few tense moments as the butterfly was carefully transferred from net to viewing pot and allowed to settle so its identity could be confirmed. Then a sudden release of baited breath and mild sting of disappointment - this wasn't the pearl bordered fritillary (Boloria euphrosyne) that we had been hoping to find but its close cousin, a small pearl-bordered Fritillary Boloria selene).

What is it? PBF or 'just' small PBF?!
Strange to think that we put such value on rarity that we should feel any sort of disappointment at seeing such a lovely butterfly up close. For the pearl-bordered fritillary is more scarce than the small pearl-bordered but the populations of both are threatened in the UK, so to come across either and capture a photograph is something of a treasure. The excitement of discovery is heightened too by the close similarity of the two species - often easily confused - the most obvious difference being the number of white 'panels' on the underside of the wings, requiring a close look for confirmation. If any further confusion were needed over the matter, the 'flight periods' of many butterfly species (the times when they are on the wing) are out of sync with the usual timings due to the long staying winter weather earlier in the year and subsequent rapid advance of summer. In the end it all adds to the excitment.

There are more ways to distinguish the two than by the under-wing patterns alone.For a more detailed comparison of the two Boloria click here or check out the Butterfly Conservation website (follow the species links above).

Definitive small pearl-bordered Fritillary

Scarce beauty - Small Pearl-bordered Fritillary

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