A large, shallow, eutrophic lake (1,300 ha), surrounded by pasture and bog.
The site regularly holds more than 20,000 wintering wildfowl. Species of global conservation concern that do not meet IBA criteria: Crex crex (6 breeding pairs).
BirdLife International (2019) Important Bird Areas factsheet: Dümmer. Downloaded from http://www.birdlife.org on 13/12/2019.