Date: 3/13/26 6:15 pm From: Jane Hadley via Tweeters <tweeters...> Subject: [Tweeters] Opinion from Amar Ayyash on the Iceland Gull ID
Hello Tweetsters -- As I reported a few days ago, opinions were very divided about the ID as to subspecies of an Iceland Gull that my husband and I saw at the mouth of the Cedar River on March 1, 2025.
(The headline on this picture page identifying it as Kumlien's was my opinion before I sought help from others via Tweeters.)
Specifically, 8 people thought it was a leucistic Thayer's Gull, 8 thought it was Kumlien's, 4 thought it was the Iceland (glaucoides) subspecies and two thought it was leucistic glaucoides subspecies. Another five people thought it was a different species altogether (Glaucous, American Herring, Ring-billed).
At the suggestion of one of our Tweeter members, I emailed gull expert Amar Ayyash to ask his opinion. I was very pleased when he replied. And here is his reply:
"I don't have a definite answer for you due to the immense overlap in both kumlieni and thayeri, and also, the seasonal effects on their pale plumages.
This could be a "real" Kumlien's Gull or, in March, a very bleached Thayer's Gull. Perhaps not safely identified to subspecies is the best answer, although here on the Great Lakes, or on the Atlantic, it would certainly default to Kumlien's [Iceland] Gull (Larus glaucoides kumlieni). I don't see a leucistic bird, however, and I don't see any need to assume nominate glaucoides is involved."
Amar Ayyash is author of the 518-page book The Gull Guide North America, which was published in 2024 by Princeton University Press. It's an excellent book.
