Ogden

It's interesting to see the difference between the bills of the male and female Tufted duck at this time of year.

Do folks agree that this is a 2nd calendar year Lesser black-backed gull, with the 3rd cy Herring gull? 

Vinicombe ('Helm guide to bird id') focuses on tertials and greater coverts:  Tertials - little patterning and almost solidly dark in LBBG, and notched in HG;   Greater coverts - "dark based" in LBBG, and "chequered" in HG.

These differences can be difficult to pick up. Some HG tertials have little notching. And it is often hard to see the bases of LBBG's greater coverts.