Gavión Atlántico vs Gaviota de Kamchatka

The Great Black-backed Gull is generally larger and bulkier than the Slaty-backed Gull, with a more robust bill. Both species have dark backs, but the Great Black-backed Gull's is jet black, while the Slaty-backed Gull's is slaty gray. Observing these differences in size and back coloration can help distinguish between the two.

Look for the Great Black-backed Gull's larger size and jet black back compared to the Slaty-backed Gull's slaty gray back. The Great Black-backed Gull also has a more robust bill.

The Great Black-backed Gull is larger and more robust than the Slaty-backed Gull.

The Great Black-backed Gull has a jet black back, whereas the Slaty-backed Gull has a slaty gray back.