Sightings:
- Black-headed Gull (adult). Monmouth County, New Jersey. 05 August 2021.
- Franklin's Gull (adult). Valdez-Cordova County, Alaska. 06 August 2021.
- Short-billed Gull (adult). Churchill & Manitoba County, Manitoba. 04 August 2021.
- Laughing Gull (adult). Monterey County, California. 07 August 2021.
- Glaucous Gull (2nd cycle). New Haven County, Connecticut. 07 August 2021.
- Lesser Black-backed Gull (adult). Sitka, Alaska. 11 August 2021.
- Presumed graellsii. p1-p5 renewed, p6 half grown, p7 missing, p8-p10 old; mirror on p9 & p10.
- Short-billed Gull (adult). Calgary County, Alberta. 11 August 2021.
- Heermann's Gull (3rd cycle). Duval County, Florida. 13 August 2021.
- The same waif that has been on the Atlantic coast since August 2019. Now in 3rd basic plumage.
- Lesser Black-backed Gull (2nd cycle). Meeker County, Minnesota. 14 August 2021.
- Lesser Black-backed Gull (3rd cycle). Harrison County, Georgia. 14 August 2021.
- Little Gull (2nd cycle). Washington County, Rhode Island. 14 August 2021.
- Sabine's Gull (adult). Cook County, Illinois. 17 August 2021.
- Lesser Black-backed Gull (3rd cycle). Banff County, Alberta. 17 August 2021.
- Thayer's Gull (2nd cycle). Kenai Peninsula County, Alaska. 18 August 2021.
- Little Gull (juvenile). Cochrane County, Ontario. 19 August 2021.
- Laughing Gull (2 juveniles). Tompkins & Broome County, New York. 19 August 2021.
- Black-headed Gull (adult). Fairfax County, Virginia. 17 August 2021.
- 3rd county record.
- Laughing Gull (juvenile). Milwaukee County, Wisconsin. 22 August 2021.
- Sabine's Gull (2nd cycle type). Fremont County, Wyoming. 22 August 2021.
- Common Gull (2nd cycle). Cape Breton County, Nova Scotia. 23 August 2021.
- Nominate canus.
- Sabine's Gull (2nd cycle type). Fairfax County, Virginia. 25 August 2021.
- Little Gull (2nd cycle). Power County, Idaho. 26 August 2021.
- Lesser Black-backed Gull (2nd cycle). Power County, Idaho. 26 August 2021.
- Laughing Gull (2nd cycle). La Haute-Cote-Nord County, Quebec. 26 August 2021.
- Slaty-backed Gull (adult). Anchorage County, Alaska. 26 August 2021.
- Sabine's Gull (adult). Dare County, North Carolina. 28 August 2021.
- Glaucous Gull (2nd cycle). Ketchikan Gateway County, Alaska. 29 August 2021.
- Sabine's Gull (adult type). Escambia County, Florida. 30 August 2021.