A Saint-Julien-en-Born, circuit du Courant de Contis et de la Plaine de Sable Blanc

The Mahourat marsh, like the Pigeon plain, is part of a type 1 Natural Zone of Ecological, Faunistic and Floristic Interest (ZNIEFF). This is a scientific tool for making an inventory of ecologically sensitive areas. This marsh is listed as a wintering and migratory stopover site for birds. Several other species such as the European cistude (a turtle) and the otter have also taken up residence here.

The gallery forest The "gallery forest" and the wooded swamps are the ecological equivalent of the bayous of Louisiana and Florida. It is likely to be home to plant species such as the swamp fern, or the St. John's wort, a herbaceous plant with yellow flowers and downy leaves. The gallery forest is an ambivalent ecological corridor (a place where species can move between several living areas), as it is both forested and aquatic.

To the south of the Courant de Contis lies the Plaine de Pigeon. It is a vestige of the wetlands drained at the end of the 19th and beginning of the 20th centuries. Managed by the ACCA of Lit et Mixe and the departmental hunting federation, this site is home to a wealth of biodiversity unique in the Landes. This breeding ground for rare species is home to several species of orchids, as well as the marsh stellar, a rare herbaceous plant in the Landes massif.

In the 18th century, the confluence of the Vignacq and Courlis rivers fed the pond of Saint-Julien et de Lit. A century later this pond split in two and gave rise to vast areas of marshland. At the beginning of the 20th century, the ponds and a large part of the associated wetlands were drained to combat an epidemic. The Courant de Contis, which was the outlet of the ponds, is now the channelized outlet of the two watercourses and of a drainage network of which the Plaine du Sable Blanc is a perfect example. This drainage system now allows asparagus to be grown.