Both gulls and terns are seabirds, of which there are over 300 different species worldwide. These only account for 3 % of all bird species, but they often appear in large numbers and colonies of a million birds have been recorded.
全世界海鳥有三百多種，只佔鳥種的百分之三，但它們出現時的數量往往頗為可觀，曾有上百萬隻聚集一處的記錄。