Monthly Notables December 2019

Sightings:

• Ross's Gull (adult). King County, Washington. 01 December 2019.
• 3rd State Record.
• Heermann's Gull (adult type). Tarrant County, Texas. 02 December 2019.
• 5th State Record.
• Slaty-backed Gull (adult). Brant County, Ontario. 06 December 2019.
• Slaty-backed Gull (adult). Niagara County, Ontario. 08 December 2019.
• Laughing Gull (adult). Sheboygan County, Wisconsin. 06 December 2019.
• Franklin's Gull (1st cycle). La Vallee-du-Richelieu County, Quebec. 07 December 2019.
• California Gull (adult). Marion County, Iowa. 08 December 2019.
• Black-headed Gull (adult). New Hanover County, North Carolina. 08 December 2019.
• Likely a returning bird for the 4th consecutive winter.
• Common Gull (adult). Pictou County, Nova Scotia. 08 December 2019.
• Slaty-backed Gull (adult). Niagara County, New York. 18 December 2019.
• Slaty-backed Gull (adult & 2nd cycle). Middlesex County, Ontario. 13 December 2019.
• Slaty-backed Gull (adult). Walla Walla County, Washington. 16 December 2019.
• Slaty-backed Gull (adult). Benton County, Washington. 21 December 2019.
• Laughing Gull (1st cycle). San Mateo County, California. 21 December 2019.
• Mew Gull (2nd cycle). Dona Ana County, New Mexico. 22 December 2019.
• California Gull (adult). Middlesex County, New Jersey. 23 December 2019.
• California Gull (1st cycle). Cameron County, Texas. 25 December 2019.
• Little Gull (1st cycle). Riverside County, California. 30 December 2019.
  
• Heermann's Gull (1st cycle). Palm Beach County, Florida. 31 December 2019.
• Continuing individual wintering on FL Atlantic coast.

Notes:

1. The adult Ross's found on Lake Washington in Seattle appeared to be ill with droopy wings and a lazy gait. After two hours of observation birders witnessed a Bald Eagle fly in and effortlessly take the gull. It was carried to a nearby tree and consumed. Not unlike the story of the adult Ross's Gull from San Mateo County, California a few years ago, these sightings reinforce the belief that ROGUs which make it this far south do not fare well. 
2. Similar to last winter, southern Ontario hosted 3-4 Slaty-backed Gulls in December. 
3. Of interest is the 10,000 California Gulls reported in Salt Lake County, Utah in early December. 

December 2019 Quiz

Age: It appears this is a large four-year gull, and judging by the plumage aspect, we can estimate it is in its 3rd plumage cycle. The adult-like, gray, inner primaries, with broad white tips are sufficient enough to steer us away from 2nd cycle, but the black secondary centers, broad tail band, marked primary coverts and brown cast to the wing coverts assure us this isn't an adult.

Identification: To begin identifying this gull, we should ask which large four-year gull has a pale eye at this age, relatively paler gray upperparts and a proportionately-sized bill. California Gull is ruled out by the pale eye. Ring-billed - a 3 year gull -  may come to mind but this is a larger and more broad-winged bird. Furthermore, 2nd cycle Ring-billeds never show tailbands this wide. Our December bird is a fairly typical Herring Gull, except perhaps for the lack of white in the outer primaries. At this age, Herrings usually show a mirror (or two) on the outer wing, but on rare occasion may not. It is worth mentioning that gray feathers mixed with brown pigments almost always make sub-adults appear darker than typical adults. Add to this an already underexposed image and the result is a bird that appears darker than what we normally associate with American Herring Gull.

Chicago. November.