| Great Black-backed Gull Identification Tips |
| (Credit: U. S. Geological Survey) |
| General
Information - Very large gull - Very large bill with distinct gonydeal angle - Flat forehead and large bill give "mean" appearance Adult alternate - Bright yellow bill with red spot at gonys - Pink legs - Yellow iris - White head, neck, breast and belly - Black mantle - White tertial and scapular crescent - Black primaries (do not contrast with back) with white tips and two white mirrors on outer primaries - White tail Adult basic - Like adult alternate but faint brown streaking on head Juvenile/First-year - Black bill - White head, neck, breast, and belly with very fine dark streaks - Back and upperwings strongly checkered with dark brown and white - Dark primaries - White tail with fine bars and black terminal band - White rump contrasts with back Second-year - Pinkish bill with black tip - Pale head, neck, upper breast, and belly , streaked finely with brown - Dull brown upperwing coverts - Black back - White tail with black terminal band Third-year - Like adult basic, but often lacks adult bill pattern, wingtip pattern, and often retains brown upperwing coverts and a partial tail band Similar species Adults and subadults older than one year are recognizable by their black mantle. All other gulls (including Lesser Black-backed Gulls) are paler backed. First-year birds are similar to other gulls in their first winter, but have very pale heads and breasts and strongly checkered upperparts, unlike any other species. First-year Lesser Black-backed Gulls are perhaps most similar in that they have white rumps and pale heads and breasts, but are very differently proportioned being smaller-billed and much longer-winged, and even smaller in size than a Herring Gull. |
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