Chalkhill Blue Butterfly: Summer Spectacle

Up early yesterday morning for a walk to and over Wolstonbury Hill to the south of Hurstpierpoint. A beautiful sunny morning with a slight breeze - the green grassland slopes looking stunning in the summer sunshine dotted with jewel like wild flower specimens. 

 


The western slope of Wolstonbury above Newtimber Chalk Pit was inundated with Chalkhill Blue (Polyommatus coridon) sometimes also called the Small Blue Butterfly, the preceding warm night had obviously stirred them as there were dozens of them flittering over the low grass and flowers with a restless energy.The Chalkhill Blue is the UK’s smallest butterfly and the caterpillars rely almost exclusively on Kidney Vetch, a plant species which is a poor competitor and which does well where soils are thin and lacking in nutrients. The grazed areas on the south downs provide perfect conditions for the Kidney Vetch, hence this morning’s Chalkhill Blue butterfly spectacle. A friend who is more knowledgeable than me reckons they are a bit late this year due to the cold Spring.

Butterfly collecting was terribly fashionable during the 19^th century and there were sites on the south downs which were kept secret by commercial collectors as there were so many butterflies to be found, the Chalkhill Blue being one of the most sough after specimens. Nowadays, a far greater threat is the encroachment of scrub which prevents Kidney Vetch from regenerating which is why grazing cattle and sheep are so vital to maintaining the ecological balance of the south downs.