Monthly Notables December 2015

• California Gull (adult). Berrien County, Michigan. 01 December 2015.
• Continuing from late November.
• California Gull (1st cycle). Whiteside County, Illinois. 05 December 2015.
• Black-legged Kittiwake (adult). Henry County, Ohio. 05 December 2015.
• Kelp Gull (adult). Summit County, Ohio. 05 December 2015.
• First State Record. Seen on-and-off throughout the month at Springfield Lake. Site used strictly for roosting. Daytime feeding site unknown, although similar to most large gulls wintering inland, a local landfill(s) is the most likely source. Interestingly, this location is within 100 miles of the January 2015 Pittsburgh Kelp Gull (also a 1st for the state of PA).
• Lesser Black-backed Gull (1st cycle). San Diego County, California. 06 December 2015.
• A different 1st cycle than November's bird.
• Black-headed Gull (1st cycle). Kings County, New York, 06 December 2015.
• Mew Gull (1st cycle). Davis County, Utah. 07 December 2015.
• Lesser Black-backed Gull (3rd cycle). Okanogan County, Washington. 08 December 2015.
• Franklin's Gull (1st cycle). Dorchester County, Maryland. 10 December 2015. 
• Iceland Gull (adult). Clallam County, Washington. 13 December 2015.
• Red-legged Kittiwake (adult type). Lincoln County, Oregon. 13 December 2015.
• 11th State Record.
• Sabine's Gull (1st cycle). Wayne County, Kentucky. 13 December 2015.
• Little Gull (2 - adult & 1st cycle). Lauderdale County, Alabama. 13 December 2015.
• Franklin's Gull (3 adults). District of Columbia. 16 December 2015.
• Iceland Gull (2nd cycle). Kootenai County, Utah. 17 December 2015.
• Continuing from late November.
• Thayer's Gull (1st cycle). Cecil County, Maryland. 18 December 2015.
• Laughing Gull (adult). Digby County, Nova Scotia. 20 December 2015.
• Common Gull (2 adults). St. John's County, Newfoundland. 20 December 2015.
• Ivory Gull (1st cycle). Whittier, Alaska. 21 December 2015.
• Black-headed Gull (adult). Cuyahoga County, Ohio. 26 December 2015.
• Franklin's Gull (1st cycle). Cuyahoga County, Ohio. 26 December 2015.
• Vega Herring Gull (adult). Volusia County, Florida. 29 December 2015.
• A good candidate that shows no field marks that are out of range for that taxon.
• Lesser Black-backed Gull (adult). Yolo County, California. 30 December 2015.
• Likely a returning individual. 
• California Gull (adult). Lake County, Illinois. 31 December 2015.

December 2015 Quiz

Mew Gull. Seattle, Washington. 03 January 2012.

It's obvious that this bird isn't an adult due to the black markings on the tail and primary coverts. The small bill and overall compact proportions immediately steer us into the Ring-billed/Common/Mew Gull arena. In that case this would be a 2nd cycle type as these are 3 year gulls.

Anyone familiar with 2nd cycle Ring-billed Gulls will find the large p10 mirror to be unusual for that species, but much more problematic is the mirror on p9 - this isn't found in 2nd cycle type Ring-billeds. If the color of the upperparts, particularly the back, is true-to-life, then this too should raise doubts about Ring-billed. Ring-billeds generally look paler and more silvery than this flat, dark, gray.

The trailing edge to the secondaries on 2nd cycle type Ring-billeds also appears thinner and less contrasty where the white and gray meet. Here's an example:

A single mirror on p10 and thinner trailing edge to the secondaries.

Given the noticeably thin, petite bill, with large, dark doe-eye, and smudgy hindneck markings, I safely identified this as a Mew Gull (L.c. brachyrhynchus).