An astonishing 300 bird species have been sighted at this 2-sq-km bird sanctuary, an important migratory stopover between the UK, Iceland, Scandinavia and Siberia and the warmer climes of West Africa. Three marked walking circuits (2km to 6km) take you to marshes, dunes, meadows, freshwater ponds, a brackish lagoon and 13 observation posts. Year-round, the park's guides – carrying telescopes on tripods – are happy to help visitors, especially kids, spot and identify birds. It's situated 9.5km northwest of Le Crotoy.
The park consists of land reclaimed from the sea in the 1960s by the construction of Dutch-style polders. Birds can be seen here year-round. Some species spend the winter, others migrate through in spring and autumn, and yet others – including white storks, grey herons, night herons, cattle egrets, little egrets, pied avocets and Eurasian spoonbills – nest from March or April to June or July. Allow at least two hours for a visit.
One-hour guided introductory walks (free) begin daily at 10.30am and 2pm; call ahead if you'd like a tour in English. The immediate vicinity has a number of lovely day-hike paths, including Sentier des Crocs (15km). The park rents out bicycles (€15/11 for a whole/half day) for rides in the area, like the Circuit de l'Avocette. Other tours include early-morning or evening birdsong tours outside of park opening hours, horse-drawn carriage rides along the seashore and bird photography lessons; prices for adults/children start from €18/10.