First of all, the Audouin's Gull; restricted in the Aegean Sea, this gull is found in uninhabited islets with a population of no more than 700 pairs (latest censuses claim that its numbers are even lower). Threatened by depletion of fish stocks, disturbance and competition by Yellow-legged.
Mediterranean Gulls are quite common in several coastal sites of Northern Greece, forming large colonies. They are also threatened by disturbance at their nesting sites.
Slender-billed Gulls are found in scattered colonies of northern and western Greece. Particularly common in the Messolonghi lagoons.