Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Jean-Michel Sauvage (France)
Morten Helberg (Norway)
Nils Helge Lorentzen (Norway)
Mars Muusse (Netherlands)

Great Black-backed Gull (Larus marinus) 3U4 September 2013 & May 2014, New York & Whiting. Picture: Brad Carlson & Amar Ayyash.

Banded as pullus on Appledore Island, July 2013. A resighting in September 2013 was reported from Rochester, New York (Lake Ontario), then about 1,000 miles from where it hatched, this 1st summer bird will likely remain on southern Lake Michigan for the rest of the summer season. It will be interesting to see if it returns in subsequent years. Very intriguing is that the Hamilton Lake Watch near Rochester reports that Great Black-backeds are almost always seen migrating "westbound" in late Fall. Perhaps the increasing Lake Michigan winter population is one that exhibits an east-west migration, and doesn't originate from as far north as thought by some.

below: Larus marinus 3U4 1st cycle (1CY), September 01 2013, Summerville Pier - Rochester, New York. Picture: Brad Carlson.

Visit Brad's Flickr photo's. Bird in completely juvenile plumage. Huge bill indicate male.

below Larus marinus 3U4 moult into 2nd cycle (2CY), May 27 2014, Whiting, Indiana. Picture: Amar Ayyash.

Visit Amar's blog.

In complete moult: P1-P3 fully growng, P4-P5 growing, P6 missing, P7-P10 old in right wing and P7 fropped in left wing. Still all secondaries and rectrices old, worn and bleached juvenile feathers. Median coverts largely replaced, except MC3 which still seems to be growing; inner GC1-GC3 replaced, GC4-GC6 & GC8 still old juvenile (GC7 broken?), central greater coverts missing, exposing the dark centres of the juvenile secondaries underneath. LLC1 old, LLC2-LLC5 replaced 2nd gen, central lower lesser coverts missing, outermost visible LLC replaced and many missing. Few single LC replaced, especially in outer tract of LC, most lesser covert feathers worn juvenile. Fresh 3rd gen upper scaps again 2nd gen like patterned, anchor-shape.