This big wetland with vast reed swamps is very good for birding, It is a breeding area of among others Marsh Harrier, Great Bittern, Bearded Tit and many other reed birds. In 2019 even a Black-winged Stilt. Tetjehorn is also the resting place for thousands of Common Starling. But also for many Great Egret and Hen Harrier. There is an observation tower from where you can oversee the area.
Accessible from Graauwedijk between Overschild and Steendam. Enter the unpaved path on the south side (with the sign "Bicycle path") and you will arrive at the watchtower.