The site consists of saltwater lagoons, beaches, saltwater marshes, woodland and arable land.
The site holds 20,000 or more waterbirds on passage, on a regular basis. Species of global conservation concern that do not meet IBA criteria: Aythya nyroca (wintering).
BirdLife International (2019) Important Bird Areas factsheet: Marais et forêt d'Olonne. Downloaded from http://www.birdlife.org on 10/12/2019.