Classified since 2012, the reserve stretches over 18 hectares and preserves a bocage area not far from Grand Lieu lake.
The Cailleries nature reserve is situated in Saint-Colomban.
With its 3700 m of country hedges, meadows and wooded lands, its 13 ponds and small lake, it is an example of the bocage landscape currently found in the Pays de la Loire région.