Two adult LBBGs had been hanging around Windsor Reservoir in Weld County, Colorado (USA) since mid-September. A third bird was present on 3 October, photographed here at the nearby landfill. The next day, 4 October, I counted 7 of these birds at the reservoir. Notice the early stage of primary replacement like the adult photographed on 20 Sep 2006 ( https://pbase.com/quetzal/lbbg9202006).

Comment on identification: In the first photo, the white head seems uncharacteristic for a LBBG in basic plumage. Body feather molt is probably in progress. Some dark markings on the head are apparent in the close-up digiscoped view of the 2nd photo. In this photo, notice the larger size compared with the California Gull to the left. LBBGs range in size from Laughing Gull size on the small end of the spectrum to Herring Gull size on the large end. The yellow legs and small size rule out Great Black-backed Gull. The head streaking and white mirror on P9 rules out Yellow-footed Gull. Yellow legs rule out Western Gull. Bill is not heavy enough for any of these three similar species.