Étang de Cousseau

Étang de Cousseau is a small lake in the commune of Lacanau, in the Gironde department of southwest France, roughly 50 km west of Bordeaux and just 3 km from the Atlantic coast. It gives its name to a surrounding nature reserve created in 1976, one of the earlier protected areas established in the Landes de Gascogne region.

Where exactly is the reserve located?

The Cousseau lake sits between the two much larger Médoc lakes: Carcans-Hourtin to the north and Lacanau to the south. The protected core covers several hundred hectares, and over time the departmental council, the town of Lacanau and the Conservatoire du Littoral have bought up neighbouring plots to widen the buffer zone around the water.

How did this chain of lakes form?

The coastline here owes its shape to wind. About 3,000 years ago, sand blown up from the beach began drifting inland, building a line of dunes running parallel to the shore. Those dunes blocked the rivers draining the Landes de Gascogne from reaching the sea, so water pooled instead in shallow basins running parallel to the coastline. That is how the Médoc's string of coastal lakes was born, with Cousseau as one link in the chain.

What did the land look like before the reserve existed?

Until the late 18th century, the area around the lake was open, waterlogged heathland, flooded in winter, where shepherds grazed their sheep freely. In the early 19th century the French state began planting maritime pine here, and that planting effort is what created the pine forest now typical of the Landes de Gascogne. The trees were harvested for timber, but also tapped for resin; a tiny hut once used by a resin-tapper still stands inside the reserve today.

What wildlife lives in the reserve?

Cousseau is best known for its birds — more than 200 species have been recorded, especially in spring and autumn. Birds of prey nest here, while ducks, common cranes and snipe arrive to winter on the lake. Reptiles include the European pond turtle, the southern smooth snake and the asp viper. Amphibians are represented by Perez's frog, the natterjack toad and two species of tree frog. Among mammals, roe deer, wild boar, badgers, hares and genets are fairly easy to spot, while the European otter is far rarer and more discreet, using the reserve's calm waters to raise its young. Since 2023 the reserve has been running a reintroduction programme for the dung beetle Scarabaeus laticollis, a species that had disappeared from Gironde — the first attempt in France to bring back an extinct insect.

What plants grow around the lake?

The dry dunes are covered with maritime pines, holm oaks and pedunculate oaks alongside strawberry trees, with ferns, gorse, broom and heather growing beneath them. In the wetter parts of the reserve grow royal fern, iris, pillwort, sundew, bog myrtle and water lilies, several of which are protected species.

Can visitors walk through the reserve?

Yes, a marked nature trail crosses the reserve on foot, taking in the pine forest, the older dune ridges and the lakeshore in turn. The site is managed by the SEPANSO Aquitaine association under a delegation from the French state, which also organises occasional guided walks.

Frequently asked questions

When was the Étang de Cousseau reserve created? In 1976, in the commune of Lacanau in Gironde.

How close is the lake to the ocean? About 3 km from the Atlantic coast, between the Carcans-Hourtin and Lacanau lakes.

What wildlife is worth looking out for? Mostly birds — over 200 species — plus the European pond turtle and, with some luck, the elusive European otter.

Is the reserve open for independent visits? Yes, a signposted walking trail runs through its main habitats.