Colin & Julian's post egg finds are very apposite at the moment. During the last decade Brown Hairstreak has reduced from over 100 sites in Tywi valley downstream of Broad Oak to ZERO. This is undoubtedly in large part due to modern farming practices of contractors flailing hedges annually. 80% of eggs are destroyed each year, which means within 5 years local extinction occurs. Only two sites are known upstream of Broad Oak - this one where Julian found eggs and Taliaris. This winter we hoped to visit more lowland fields in this area, but awaiting COVID restrictions being eased. However, if you are out walking in the area and below 100m altitude, you might be lucky and spot eggs on unflailed blackthorn.