Mai Po nature reserve sits on the border across Hong Kong and mainland China. There is a no mans land called the Frontier Closed Area or FCA where a mangrove ecosystem and estuary into Deep Bay is a wading area for birds. Looming in the background is the ever growing city of Shenzen pushing right up to the edge of the reserve. As the tide comes in from left to right the birds march with it looking for mudskippers and fish.