Audouin’s Gull colonized Apulia region, SE Italy, around 1990. Regular surveys were performed since 2016, revealing an increase in the number of breeding sites and population size. The top value was reached in 2020, when a new colony, representing the most important settlement in the Adriatic Sea as well as in the entire eastern basin of the Mediterranean has been discovered near Brindisi. This settlement hosted a maximum of 222 breeding pairs. In 2020-2022, when the coverage was complete, the Apulian population of Audouin’s Gull fluctuated between 339 and 617 breeding pairs and occupied a total of five islands, with an overall production of 703 fledglings. Details are provided in order to enhance the designation of new or enlarged Natura2000 sites.