Lesser Black-backed Gull
Larus fuscus
The lesser black-backed gull is smaller than the European herring gull. The taxonomy of the herring gull / lesser black-backed gull complex is complicated; different authorities recognise between two and eight species. This group has a ring species distribution around the Northern Hemisphere. Differences between adjacent forms in this ring are fairly small, but by the time the circuit is completed, the end members, herring gull and lesser black-backed gull, are clearly different species.
ID text from Wikipedia, CC BY-SA 4.0
Ring-billed Gull
Larus delawarensis
The ring-billed gull is a medium-sized gull, having an average length of 43 to 54 centimetres (16.9 to 21.3 in) and a wingspan that ranges from 105 to 117 centimetres (41.3 to 46.1 in). Adults weigh from 300 to 700 grams (10.6 to 24.7 oz). The head, neck and underparts are white; the relatively short bill is yellow with a black ring; the back and wings are silver grey with black wingtips with white 'mirrors'; and the legs are yellow. The eyes are yellow with red rims.
ID text from Wikipedia, CC BY-SA 4.0
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