Brown Hairstreak (Thecla betulae), Buckinghamshire
The Brown Hairstreak deservedly has a reputation for being one of the more difficult butterflies to photograph. It is genuinely uncommon, occuring at lower densities than the other hairstreaks, and it also has a highly localised distribution in southern Britain. It also tends to keep out of camera's reach in the tops of trees and Blackthorn hedges, though it is sometimes tempted lower to feed on flowers.
It is so elusive that Butterfly Conservation cannot give a population trend. Surprisingly, most records are of eggs found during winter. It has definitely contracted its range since the 1970s, possibly due to flailing of Blackthorn hedgerows during winter.
It is one of a few butterflies to be named after a real person. Thecla was a virgin and martyr, commemorated by the Greek Orthodox Church. Betulae is Latin for Birch, yet its caterpillars feed on Blackthorn (Prunus spinosa), and surprisingly Linnaeus (the author) knew this.