Herring with virtually nor mirror on p10 (still growing). P4 with small speck on outer web and marked p-coverts/alula suggest a 4th cycle type. Michigan City, IN. 07 October 2016. |
Same individual above. A mostly adult-like bird near finishing prebasic molt. |
Another adult type with a large p10 mirror showing several white "spots" on the underside of the primary. P-9 with a weak thayeri pattern. Michigan City, IN. 07 October 2016. |
Adult type Herrings. Left bird already in nonbreeding condition while the bird on the right has bright legs and bill. The most natural explanation for this is hormonal variance. |
1st cycle Herring with ~90% of scapulars 2nd generation. Bill is beginning to pale. Also of interest on this bird is a paling forehead, an attribute often found in similar-aged California Gulls. |
2nd cycle Herring Gull. A very obvious marbling to the greater coverts and tertials, unlike in 1st cycle birds. The primary tips are rounded (and still growing - see next image). |