I really enjoy my visits to Warham Camp in the summer. The two huge ring ditches that surround the 2,000 year old Iron Age fort are made of chalk. This has created a rare habitat for Norfolk and many beautiful plants grow on the steep sides, these in turn support a healthy population of fascinating insects including the Brown Argus (Aricia agestis).
Last week while watching the Common Blues I was keeping my eyes open for this small butterfly. Due to size, colouration and the speed they move at they can be difficult to spot, however they are fiercely territorial and will launch themselves at any unsuspecting passing insect, and this is what gave away the presence of this fellow. Unfortunately for me he had chosen a bed of stinging nettles to defend, and although he allowed me to approach to within a few inches, I swear you could hear him laugh as my knees got badly stung!
The Brown Argus is found in the southern half of the UK. It has a wingspan of 25-31mm (1- 1 1/4 inches). The caterpillars feed on common rock-rose or cranesbill. The adults emerge in May and June with a second brood late July through to September. They prefer sunny chalk downs but can also be found in coastal sites.