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Keywords from Image Description:
Plate of British Birds by Archibald Thorburn. Richardson's Skua Stercorarius parasiticus crepidatus en Great Skua Stercorarius skua en Pomarine Skua Stercorarius pomarinus en Longtailed Skua Stercorarius longicaudus or en Parasitic Jaeger Stercorarius parasiticus Labbe de Richardson Stercorarius parasiticus crepidatus Grand Labbe