The wetlands around the Mai Po Marshes and Inner Deep Water Bay in the northwestern corner of Hong Kong have been known as a haven for migratory birds for many decades.
The original managers of Mai Po, the gei wai shrimp pond operators, used to completely drain down their gei wai to harvest the fish inside the pond when the shrimp-harvesting season has ended from early winter.
When the gei wai is drained, the areas of shallow water or exposed mud on the pond floor would provide feeding and roosting habitats hundreds of for fish-eating birds, particularly herons, egrets and the endangered Black-faced Spoonbill. Since this traditional form of gei wai management can contribute to the ecological value of the site, WWF Hong Kong is continuing with the winter drain down of the gei wai on a rotation ba sis , one gei wai is drained every two weeks from November to March, in order to provide feeding habitat for the migratory waterbirds that passing through, or winter in Deep Bay.
In order to provide the best views for visitors of the many waterbirds in the draining gei wai , a net-screen will be placed across the Closed Area Fence Road end of the gei wai when they are drained, so that visitors can see the impressive numbers of herons, egrets and Black-face Spoonbills feeding and roosting in the draining pond.