In 2020, during the COVID-19 lockdown, Gareth Tilley, an amateur lepidopterist from Epsom, Surrey, made a significant discovery of a rare butterfly species known as the black hairstreak. This butterfly had never been recorded in Surrey before, as its known habitat was limited to woodlands between Oxford and Peterborough. Tilley's discovery was not only remarkable for its rarity but also for its implications for conservation efforts in the UK, where the species has seen a 33% decline in distribution since 2002 due to habitat loss. Following his initial sighting, Tilley collaborated with Butterfly Conservation, the local council, and the University of Sussex to confirm the presence of the black hairstreak in Surrey. The species is notoriously difficult to monitor due to its unique life cycle; the caterpillars resemble leaves, the chrysalises mimic bird droppings, and the adult butterflies tend to stay high in trees. This makes traditional monitoring methods ineffective, prompting Tilley to seek innovative solutions. In May 2022, Tilley learned that some caterpillars in the United States glow under UV light, which inspired him to purchase a UV torch to search for the black hairstreak caterpillars. Initially skeptical about the effectiveness of this method, he was astonished to find that the caterpillars not only glowed but were incredibly bright. In one evening, he discovered 46 caterpillars, marking a significant breakthrough in the monitoring of this elusive species. The discovery has garnered attention from conservationists, with Pete Hughes from Butterfly Conservation acknowledging the importance of Tilley's work. The organization is now promoting UV surveying techniques for hairstreaks across the UK, recognizing the potential for this method to enhance conservation efforts. Tilley is also sharing his findings with conservation groups in Australia, further extending the impact of his discovery on global conservation practices.