If you know nothing about birds, the Parc Ornithologique du Marquenterre will be a revelation. The landscape is beautiful and strange: all dunes, tamarisks and pine forest, full of salty meres and ponds thick with water plants. You can hire binoculars; otherwise, rely on the guides at some of the observation huts, who set up portable telescopes and will tell you about the nesting birds. There’s a choice of itineraries – two longer, more interesting walks and a shorter one. On both you can see dozens of species – ducks, geese, oyster-catchers, terns, egrets, redshanks, greenshanks, spoonbills, herons, storks, godwits – most taking a breather from their epic migratory flights. In April and May they head north, returning from the end of August to October; in early summer the young chicks can be spotted.