Between Villers-sous-Ailly and Bouchon there is a steep 'larris' (limestone upland) with arid areas and patches of woodland. Like most hillsides in the Somme valley, this 'larris de Bouchon' was used for many years by shepherds. It became covered in scrub and brush when sheep no longer grazed there. Clearing work was carried out by volunteers but, above all, by hungry goats. Depending on the season, you can see common pasqueflowers in bloom, yellow rock roses or wild orchids. You may spot a common blue butterfly in flight or a Swallowtail, the largest butterfly in the region. Take care! Check out which days are designated for hunting because the path is closed then. You pass alongside the boundaries of private properties.