Tuesday, December 9, 2014

Great Black-backed Gull

On 6 December 2008, when I found the Glaucous Gull in the last post, I also photographed a number of other interesting gulls near the Black Dog power plant in Dakota Co., Minnesota. The pale head, pale, specked body, and black wing tips combine with the heavy, black bill to identify this Great Black-backed Gull. The gulls behind the Great Black-backed Gull are probably Herring Gulls, the dark one being a first year bird.

Great Black-backed Gulls are common in northeastern North America and in Europe. They winter south to the Gulf of Mexico. Feather hunters and egg collectors almost caused this species' extinction. Great Black-backs made a remarkable recovery, and by the 1960s, North American populations probably exceeded their historical numbers and now may be displacing Herring Gulls in New England breeding colonies (Good 1998).

How many gull species are flying in the bottom photograph (taken the same day as the top photo)? I think I can count Great Black-backed (upper left, lower center), Herring (right center), Thayer’s (left center), and, at the lower left, one Iceland gull. The Thayer’s and Herring differ in that the Thayer’s has a reduced amount of black on its wingtip. The Iceland is smaller than a Glaucous Gull, but like the bigger bird, has unmarked wingtips. I have commented on all of these species elsewhere in this blog.

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