The Zwin: a unique combination of a visitor park and a nature reserve, originally founded by Count Léon Lippens. There is a constant coming and going of birds in the Zwin Nature Park; in spring many return from their wintering area in the deep south to land at their brooding areas in the north; in autumn they set out on their journey in the opposite direction.
Numerous species of birds follow coastlines and use estuaries and other nature areas to rest for a while or to find food. You can compare it with aircraft that must make as stop during a long-haul flight to refuel at an airport. For very many migratory birds that follow the coastline, the Zwin is an important layover point on their long journey. The Zwin area is an airport, but one reserved exclusively for birds, the 'International Airport for Birds'!
The Zwin also famous with its rare landscape: a natural transition from one biotope to another is visible here, from beach to dunes on the one hand and from beach to mudflats and salt marshes on the other. Mudflats are flooded by the sea twice a day, at high tide, and feature no or hardly any vegetation. The salt marshes on the other hand feature a rich flora which has adapted to its surroundings. Salty mudflats and salt marshes are rare along the coasts and river mouths of Western Europe and they are under European protection.
https://www.zwin.be/en