01 August 2016

Monthly Notables July 2016

Sightings

  • Franklin's Gull (adult). Rimouski-Neigette County, Quebec. 01 July 2016.
  • Herring Gull (4th cycle type). San Diego County, California. 02 July 2016.
  • Great Lakes Gull (adult type). Delta County, Michigan. 05 July 2016.
    • Putative Herring x Great Black-backed Gull, tending toward GBBG. Presumably reoccurring in the region since at least 2012. Noteworthy is that not many Great Lakes hybrids are seen/reported in the summer months. Initially reported as a Slaty-backed Gull.
  • Franklin's Gull (adult). Essex County, Massachusetts. 07 July 2016.
  • Laughing Gull (1st summer). Capital County, British Columbia. 08 July 2016.
  • Glaucous Gull (2nd summer type). Essex County, Ontario. 08 July 2016. 
  • Lesser Black-back Gull (1st summer). Cook County, Illinois. 11 July 2016.
  • Little Gull (adult type). Fulton County, Illinois. 12 July 2016.
  • Western Gull (adult type). Alamosa County, Colorado. 14 July 2016.
    • Continuing from June 2016.
  • Laughing Gull (2nd cycle type). Kiowa County, Colorado. 16 July 2016.
  • California Gull (2nd summer type). Kenai Peninsula County, Alaska. 17 July 2016.
  • Lesser Black-backed Gull (1st summer). Glaveston County, Texas. 18 July 2016.
  • Western Gull (2nd summer). Washington County, Colorado. 18 July 2016.
    • Continuing from June 2016.
  • Lesser Black-backed Gull (1st & 2nd summer). Washington County, Colorado. 18 July 2016.
    • Now with 2-3 birds summering in the state annually. 
  • Lesser Black-backed Gull (1st summer). Portage La Prairie, Manitoba. 21 July 2016.
    • Continuing from June 2016.
  • Slaty-backed Gull (adult). Pierce County, Washington. 21 July 2016.
    • Possibly summering. Presumed to be a reoccurring individual from the last several winters.
  • Mew Gull (1st summer). Humboldt County, California. 27 July 2016. 

Notes 

  • A pair of Bonaparte's Gulls was documented nesting in far northeast Maine. Incubating was observed, but the nest failed. The site (undisclosed) is beyond the southeast terminus of the species' known breeding range. Bonaparte's aren't known to breed anywhere in the lower 48 states.
  • Up to 15 Black-legged Kittiwakes are summering in Barnstable County, MA. Although not as spectacular as last July, Cape Cod remains the farthest south this species summers - anywhere in the world! All of the MA birds are 1st summer individuals.
  • At least 2 juvenile Sabine's Gulls were seen on a pelagic trip in San Mateo County, CA on 16 July 2016. I was unable to find an earlier date for juvenile SAGU this far south in North America.
  • Indiana reported a record high of Bonaparte's for July (and the summer season in general): 133 - all but 2 adults - migrating on Lake Michigan. 30 July 2016. 

July 2016 Quiz

Berrien County, Michigan. 08 November 2015.

Age

The immaculate, fresh, plumage is all juvenile (i.e., 1st basic). The pale edges to the upperparts and pointed primary tips reinforce the fact that these are all 1st generation feathers.

Identification

I don't blame those folks who identified this month's bird as a young Thayer's Gull - indeed, there may be some thayeri that match this. But this isn't a Thayer's.

I identified this month's quiz bird as a juvenile American Herring Gull. The bill seems petite and shorter than usual, although that's likely because it's still growing. Notice how the base of the lower mandible is paling - a subtle hint that this may not be a Thayer's as that species does a better job of keeping a black bill at this age than other large gulls (but it's not terribly uncommon for a 1st cycle Thayer's to show a paling bill, especially late in the winter season before departing north). In Thayer's, the outer primaries are typically paler than the "almost black" appearance seen here, and the edges to those primaries are paler - often more so than the quiz bird. Also, most juvenile Thayer's will show tertials that are a smidgen paler than this.

Here's a more typical appearance for a similar-aged Thayer's Gull:

LaPorte County, Indiana. 27 November 2014.
Note that the outer primaries are more brown (compare with the black bill), with paler proximal edges. The upperwing coverts, too, look more marbled and frosted than in most juvenile Herrings.

The reader will note that the plumage aspect seen on our Herring Gull is one that soon becomes uncommon as December approaches, and certainly so later in the season. We do, however, see some American Herrings that retain this fresh plumage aspect later in the winter, and it's believed these birds - with more durable juvenile plumages - have likely originated from more northern latitudes. Here's one such bird found all the way south in Florida in late January:

Brevard County, Florida. 25 January 2016.
Structurally, the bird is plump and the head is large and blocky, complemented by a heavy bill. The primaries are dark - darker than the bill. Not much about this bird suggests Thayer's Gull.

My purpose in selecting a fresh juvenile Herring for this month's quiz is two-fold: To point out just how immaculate some juvenile American Herrings can look in their hatch year, and two, to emphasize the importance of how a date can greatly aid in the identification process. Without a date, it's difficult to gain any appreciation for seasonal factors such as molt and wear.