Wong Nai Chung Gap is between Happy Valley and Sham Wan, in the central part of Hong Kong Island. There are a number of streams converging. Many uncommon plants occur in the valley below. Some crow butterflies also overwinter in the valley in large numbers. But in recent years, FEHD moved the streamside rocks to in an attempt to get rid of mosquitos. Rather than achieving this goal, the act instead severely impacted the natural stream and its organisms.