The Brown Hairstreak is an elusive butterfly that spends most of its life either high in the tree canopy or hidden amongst hedgerows.  It is worth looking up at prominent Ash trees along wood edges to see if small clusters of adults may be flitting around a 'master' tree where they congregate to mate and feed on aphid honeydew.  Alternatively, adults sometimes feed lower down on flowers such as Hemp-agrimony, Common Fleabane, and Bramble.  The females are most frequently seen as they disperse widely along hedgerows where they lay conspicuous white eggs on young Blackthorn.  The butterfly is locally distributed in southern Britain and has undergone a substantial decline due to hedgerow removal and annual flailing, which removes eggs.