31 August 2020

August 2020 Quiz

Massachusetts. July. 

Age: The outer primaries on both individuals are tattered and faded, but the upperparts are largely new. There are obvious molt gaps throughout the upperwing coverts, especially the greater coverts. Both birds appear to be in their 2nd molt cycle with retained juvenile primaries

Identification: The size difference seen here is real, as can be seen from the bill and head dimensions, as well as body and leg girth. The individual on the left is a standard 2nd cycle Great Black-backed Gull with white body, checkered upperparts and a stout bill. On the right, we see a thin bill, sleek rear to the body, and what looks like a svelte, long-winged gull. The upperparts are too solidly dark and checkered for a 2nd cycle Herring, and the clean white underparts also don't evoke thoughts of that species. This bird is a Lesser Black-backed with a somewhat cleaner white head and neck than average, and upperparts that still don't show any signs of adult-like gray. The bicolored bill is also more advanced than many similar-aged Lessers which typically have more black blended through the bill base. Here's my idea of a more average-looking LBBG for comparison.

Of interest here is that GBBG and LBBG don't often look this similar at one year of age, but these two are surprisingly similar. Size and structure are very helpful here.

01 August 2020

Monthly Notables July 2020

  • Glaucous Gull (2nd cycle). Glynn County, Georgia. 01 July 2020.
    • Continuing from June.
  • Lesser Black-backed Gull (2nd cycle). Clark County, Ohio. 02 July 2020.
  • Black-legged Kittiwake (adult type). Del Norte County, California. 08-18 July 2020.
  • Franklin's Gull (2nd cycle). Orange County, New York. 10 July 2020.
  • Glaucous Gull (2nd cycle). Talbot County, Maryland. 10 July 2020.
  • Slaty-backed Gull (adult). Kenai Peninsula County, Alaska. 10 July 2020.
  • Black-headed Gull (adult). Lorain County, Ohio. 11 July 2020.
  • Sabine's Gull (adult). Barnstable County, Massachusetts. 12 July 2020.
  • Heermann's Gull (2nd cycle). Duval County, Florida. 12 July 2020.
    • Present on the eastern FL coast since August 2019. 
    • Now well into its 2nd prebasic molt with p1-p7 replaced. 
  • California Gull (2nd cycle). Alfalfa County, Oklahoma. 15 July 2020.
  • California Gull (2nd cycle). Springfield County, Illinois. 19 July 2020.
  • Great Black-backed Gull (2nd cycle). Mobile County, Alabama. 19 July 2020.
    • Continuing from June. 
  • Ring-billed Gull (adult). Skagway-Hoonah-Angoon County, Alaska. 19 July 2020.
  • California Gull (2nd cycle). Delaware County, Ohio. 21 July 2020.
  • Black-headed Gull (juvenile). Dillingham County, Alaska. 22 July 2020.
  • Franklin's Gull (adult). Barnstable County, Massachusetts. 26 July 2020. 
  • Franklin's Gull (2nd cycle type). Prince County, Prince Edward Island. 27 July 2020.
  • Laughing Gull (adult type). Keith County, Nebraska. 28 July 2020.