The bird reserve at the heart of the Baie de Somme national nature reserve, and one of the serious ornithological sites in Europe — over three hundred species recorded across two hundred hectares of dune, pine, marsh and brackish lagoon. Spring and autumn migration are the spectacle; in winter the lagoons fill with wildfowl, and in summer the spoonbills and avocets breed.
Three marked circuits of roughly two, four and six kilometres link thirteen observation hides. Naturalist guides are stationed along the route with telescopes and will find things for you that you would walk straight past, which is the difference between a nice walk and actually seeing anything. Beyond general admission there are booked guided outings — dawn visits, dusk walks, wader-identification sessions, migration weeks and a family "Big Day" species hunt.
It is about eight kilometres north of Le Crotoy at Saint-Quentin-en-Tourmont. Open daily 10am to 7pm with last entry at 5pm; admission around €12 for adults and €8.60 for children, with guided outings from €16 to €26. Bring binoculars if you have them and boots if it has rained.