ML639915775

観察結果の詳細

Our initial impression for this first cycle gull was Iceland (Thayer's) Gull based on small, all dark bill and stubby legs, giving bird a squatty look. Larger and bulkier than accompanying RBGUs. Dark auricular present with dark eye. Main structural con for Thayer's is the sloped forehead. Forehead a better fit for Herring. In terms of plumage, most Thayer's I've observed give a more checkered pattern on coverts and scaps (of course this is an August gull - juvenal plumage?). These feathers are also highly tapered and seem long. I'm perplexed with this one. Recent discussion with other Oregon birders suggests juvenile California Gull, which seems probable based on further comparisons to photos.