The great black-backed gull is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. Great Black-Back Gulls are more aggressive predators than the more common Herring Gulls (Larus argentatus), and there is particular concern about their impact on Common Eider (Somateria mollissima) ducklings. Large stout-bodied gull, with broad wings, a thick neck, and a heavy.