These birds were photographed on the bay side of Duxbury Beach(MA) about 1/2mi above High Pines (3/4-11/2009). They appear to be a 3rd or 4th year American Herring Gulls. What appears to be a black spot on the flank is actually dark greater primary coverts. After studying both gull books [Gulls of the Americas (Howell and Dunn) and Gulls of North America, Europe and Asia (Olsen and Larsson)],one quickly realizes that aging birds like these in the field is a very inexact science! Pix 1-5 were taken 3/10 and all of Bird 1. Bird 2 was found 3/11. I believe it to be further along in 4th year molt due to p9 moon and whiter head. Pix 6-7, 8-9,10-11 show Bird 2 and then Bird 1 for comparison. I have posted additional comments under each of the picture titles.