Hartsø is a partially drained lake surrounded by large reed forest areas and grazed meadows. Original lake area of approx. 45 Ha. Over time, the area has been an important breeding and resting place for waterfowls, especially geese, but other bird species can also be observed. On good days, the western marsh harriers are often seen soaring over the reeds.
Originally, the south coast of the Kegnæs peninsula had the character of an open, shallow sea bay that was cut off from the sea over time by a migrating sand bar as a result of coastal levelling. The bay became a beach lagoon that changed character to a shallow freshwater lake.
Over time, several attempts have been made to dewater the area with a view to cultivation, but this has, fortunately for the birdlife, never been completely successful. However, the water level is lower and the species diversity is not like "in the old days". Of mammals, it has been observed i.a. otters, but unfortunately also invasive species (species that do not occur naturally in Denmark) such as raccoons, mink and common raccoon dogs. The invasive species can be hard on the breeding birds and attempts are therefore made to control them.
There is a small bird tower (house) in the immediate vicinity of the car park at Tiny Seaside. GPS: ( N 54,86366 , E 9,9141)
If you want a nice view over the Baltic Sea south of Kegnæs, you can follow the asphalt road approx. hundred meters to the west, where there is good access to a view of the sea.
At the entrance to Møllegården you can see a stone on which is marked how high the water was at the storm surge of the century on 13 November 1872. On this day the water level in the western Baltic Sea was up to 4 meters above normal water level, with disastrous consequences for e.g. Kegnæs. Large areas were flooded during this event, resulting in tragic human fates and material damage.
Hartsø can be visited all year round, but if you want to see large flocks of waterfowls, the winter months are best. Here the water level is highest and the area is much visited by migratory birds.