An important ornithological site, the Salins d'Hyères are subject to birds counts on a regular annual basis of 10-day periods. Such frequency allows the optimal detection of pre-nuptial and post-nuptial migratory movements as well as the overwintering of some of the 312 listed species. These counts are carried out at sunrise, which corresponds to a peak in bird activity, particularly vocal, and helps limit reverberation and heat mists that are harmful to the birds' visibility.