American Herring Gull (smithsonianus)

(last update: October 30, 2015)

American Herring Gull 4cy March

GULLS OF THE AMERICAS

- Steve N.G. Howell / Jon Dunn -

Below is a copy of chapter 25 about American Herring Gull, illustrated with images from this website. "we" in the text below refers to the original authors. If any errors occur in this text, please let me know and mail to marsmuusseatgmaildotcom.

American Herring Gull (smithsonianus)

PART 1: IDENTIFICATION SUMMARY

PART 2: FIELD IDENTIFICATION - ADULT CYCLE

PART 3: FIELD IDENTIFICATION - FIRST CYCLE (BELOW)

First Cycle.
American Herring Gull is common but notoriously variable, and it should be learned thoroughly. In e. N. America the only other regular dark-winged large gulls are Great Black-backed and rarer Lesser Black-backed. In the West, several potentially similar species occur; also see hybrid American Herring Gull accounts (pp. 482-485 in Gulls of the Americas). Features to note are the relatively long and narrow wings; relatively parallel-sided bill with variable pinkish basally; blackish to brownish black wingtips and tail; and a pale upperwing panel on the inner 5-6 primaries. Relative to other N. Atlantic species, relatively plain brownish underparts of American Herring are distinctive. East Coast types (see Description) average earlier PA1 molt and typically have more solidly blackish tail, whereas West Coast types (see Description) molt later on average and often have whitish at tail base.

American Herring Gull (smithsonianus) 1st cycle ACX January 07 2012, Merritt Island, FL (Danny Bales). Banded as pullus in 2011 at Portland, ME. Rearscaps still juvenile.	American Herring Gull (smithsonianus) 1st cycle 1106-13848 December 07 2013, New Buffalo, MI (Amar Ayyash). Banded on June 24 2013 in Door County WI. Bi-coloured bill. All scaps replaced.
Thayer's Gull first cycle, January 28 2012, Pacific County, WA (Charlie Wright). Few scapulars replaced for 2nd generation feathers.	Thayer's Gull 1st cycle, February 16 2010, Winthrop Harbor, IL (Erik Bruhnke). Note pale windows on inner primaries which continue to the inner webs of the outer primaries. Also note the lack of dark pigmentation on the inner web tips of P1-P4, with just a bit of faint darker on P4.

THAYER’S GULL averages smaller with a more slender bill that generally has a less distinct gonydeal expansion and often shows slightly steeper and more rounded forehead. Plumage overall slightly to distinctly paler than Herring Gull, blackish brown to medium brown wingtips usually have distinct whitish fringes, upperparts often with coarser and more checkered, or marbled, pale patterning. Inner webs of outer primaries more extensively pale so that pale inner primary panel on upperwing bleeds into distinctly two-tone outer primaries; underside of outer primaries paler, more silvery gray (but can be reflectively pale on Herring). Tail typically dark brown (blackish to blackish brown on Herring).  Some darkly pigmented Thayer’s can be very similar to Herring Cull (or hybrids), and problem birds may not be identifiable.

Great Black-backed Gull (marinus) 1st cycle JM07 March 05 2007, IJmuiden, the Netherlands (Mars Muusse). Probably male, banded in Norway.	Great Black-backed Gull (Larus marinus) 1st cycle, December 15 2012, IJmuiden, the Netherlands (Mars Muusse). Thin tail band.
Lesser Black-backed Gull (graellsii) 1st cycle HC63 November 21 2010, Madrid, Spain (Delfín González). Banded in N Germany. Most scapulars still juvenile, wing-coverts and tertials still juvenile.	Lesser Black-backed Gull (graellsii) 1st cycle, April 10 2011, Agadir, Morocco (Frode Falkenberg). P1-P10 still present, hence complete moult not started. Post-juvenile moult on winter grounds included all scaps but also several injner wing-coverts and upper tertials. Note dark inner primaries.

GREAT BLACK-BACKED GULL (e. N. America) larger and more massive overall with more bulbous-tipped bill. Head and underparts whiter and upperparts more boldly checkered; uppertail coverts and tail contrastingly white with clean-cut black distal tail banding; underwings paler brownish overall, contrasting with white body; upperwings rarely with distinct pale panel on inner primaries.

LESSER BLACK-BACKED GULL (widespread but rare in West) averages smaller and slimmer with narrower wings, longer wing projection, and slimmer, all-black bill. Upperparts (including tertials) average narrower pale edgings. Primaries overall dark with no or very indistinct paler panel on inners; bases of greater coverts more often solidly dark brown. Uppertail coverts and tail base contrastingly white with clean-cut, black distal tail band.

California Gull (californicus) 1st cycle, October 27 2012, New Buffalo, MI (Amar Ayyash). By October already bi-coloured bill and advanced post-juvenile moult, including 2x GC.	California Gull (californicus) 1st cycle, July 30 2010, Qualicum Beach, BC (Guy Monty). Juvenile, with dark inner primaries.
California Gull (californicus) 1125-06236 1st cycle, September 12 2014, Half Moon Bay, CA. (Amar Ayyash).

CALIFORNIA GULL averages smaller with longer wing projection (tail tip about equal with tip of P6), narrower and more crooked wings in flight, and more parallel-sided bill that, by Oct., is typically flesh pink with a clean-cut black tip (also shown by some Herrings); its pinkish legs often have a bluish hue on the tibia and joints. Primaries overall dark with no or very indistinct paler panel on inners, bases of greater coverts more often solidly dark brown. PA1 molt generally extensive (often includes upperwing coverts) and earlier than Herring Gull.

WESTERN GULL (w. N. America) larger and bulkier with a stouter, rather bulbous-tipped bill, broader wings (often shows a skirt). Dark sooty brownish overall, A1 scapulars typically have blackish centres and grayish to pale brownish edgings (not the barred pattern common on Herring), primaries overall dark with no or very indistinct paler panel on inners, tail solidly blackish; typically does not get whitish-headed look common on first-winter Herring Gull.

Western Gull (occidentalis) 1st cycle, November 18 2006, Bolsa Chica, CA (David Marotta). Note the dark mask of a Western Gull and the rather dark plumage including tertials.	Western Gull (occidentalis) 1st cycle, November 08 2010, Oregon (Hartmut Walter). Dark outer primaries.
Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Piano key pattern on GC but hardly any notching on TT. Scap moult: 50-75%.	Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Atypical bird in a European context, with no notching on tertials (and tertials darkest part of bird together with visible primaries like in cachinnans) and very simple pattern on 2nd gen scaps.
Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Very similar to European Herring Gull. Piano key pattern on GC and deep notching on TT. Scap moult: 75-99%.	Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Overall pale impression maybe better fits mongolicus. Pale grey-brown base colour of scaps suggest these feathers were replaced quite recently, and still not bleached. Scap moult: 100%.
Vega Gull (vegae) 1st cycle, January 25 2011, Choshi, Japan (Terry Townshend). Dark secondary bar. Pale panel on inner primaries reaching outer secondaries S1-S3 and still innerweb of P6 largely pale.	Vega Gull (vegae) 1st cycle, January 27 2011, Choshi, Japan (Terry Townshend). Very similar to European Herring Gull. 1st gen flight feathers. Tail pattern typical. Beginning to gain some grey scapulars.

VEGA GULL can look very similar (and perhaps not always safely distinguishable) but underparts average paler overall and does not attain strongly bicolored bill. Tail coverts and tail base whiter with less-extensive dark barring, tail has narrower blackish distal band than most American Herring Gulls.

Slaty-backed Gull (schistisagus) 1st cycle, December 27 2009 - January 04 2010, Choshi, Japan (Chris Gibbins). Bulky bird. Uniform primaries (with none of the strong patterning (spots, bars) so evident in P1-5 of Vega and Herring Gulls of this age) and uniform greater coverts. Plain tertials and simply patterned second generation scapulars.	Slaty-backed Gull (schistisagus) 1st cycle, December 27 2009 - January 04 2010, Choshi, Japan (Chris Gibbins). Bulky bird. Smithsonianus-like rump and tail pattern, uniform primaries and uniform panel formed by the greater coverts. The underwing coverts are very uniform, softly patterned with brown.
Slaty-backed Gull (schistisagus) 1st cycle, January 31 2010, Choshi, Japan (Gullog). About half of the scapulars replaced. Tail almost completely dark. Much white in GC in this bird give this bird a Vega-look.	Slaty-backed Gull (schistisagus) 1st cycle, December 27 2009 - January 04 2010, Choshi, Japan (Chris Gibbins). Uniform primaries with none of the strong patterning (spots, bars) so evident in P1-5 of Vega and Herring Gulls of this age, and the uniform panel formed by the greater coverts.
Slaty-backed Gull (schistisagus) 1st cycle, February 13 2013, Rausu, Japan (Mike Buckland). Bulky bird. Few upper scapulars replaced. Simple tertial pattern.	Slaty-backed Gull (schistisagus) 1st cycle, February 13 2013, Rausu, Japan (Mike Buckland). Bulky bird. Few upper scapulars replaced. Simple tertial pattern. Note skirt.

SLATY-BACKED GULL (n. Pacific) averages heavier bodied and broader winged. Has plainer and paler greater coverts, A1 scapulars typically with dark shaft streaks or dark centers (like Western Gull) rather than paler gray with dark cross-barring or anchor patterns (typical of Herring). Outer primaries have more-extensive and more-contrasting pale on inner webs (so pale inner primary panel contrasts less strongly and spread upperwing often shows pale tongue-streaks on outer primaries). Whiter-looking tail coverts have sparser dark marks and often contrast more strongly with mostly dark tail.

Yellow-footed Gull (livens) adult, January 30 2009, La Paz, Baja California, Mexico (Amador). Already on structure not like Herring Gull.	Yellow-footed Gull (livens) 1st cycle, August 09 2010, Salton Sea, CA (Amar Ayyash). Dark inner primaries.

YELLOW-FOOTED GULL (Gulf of Calif.) larger and bulkier with much stouter, bulbous-tipped bill, broader wings (often shows a skirt at rest). Belly and tail coverts white with sparse dark bars, A1 scapulars typically darker and more uniform than Herring (and PA1 often includes upperwing coverts and tertials), primaries overall dark with no or very indistinct paler panel on inners, tail solidly blackish.

Olympic Gull (occidentalis x glaucescens) 1st cycle, October 15 2006, Vancouver Island, BC (Guy Monty). Intense mottling with brown (not black) primaries.	Olympic Gull (occidentalis x glaucescens) 1st cycle, October 28 2011, Clallam County, WA (Steve Mlodinow). Note the dark mask of a Western Gull and the rather dark plumage overall with more GW Gull like primaries. Overall much bulkier than Herring Gull.
Nelson's Gull (smithsonianus x hyperboreus) 1st cycle, November 08 2009, Palmer Landfill (Kirk Zufelt). Like Glaucous Gull, except dark pigmentation in the outer primaries (Herring influence).	Nelson's Gull (smithsonianus x hyperboreus) 1st cycle, January 14 2007, Sault Ste. Marie Landfill (Kirk Zufelt). Like Glaucous Gull, except dark pigmentation in the outer primaries.

HYBRID GLAUCOUS-WINGED GULL X WESTERN GULL more thickset with broader wings (usually showing a skirt), stouter and more bulbous-tipped bill; can show pale panel on inner primaries suggesting Herring but outer primaries generally paler (dark brown versus blackish); tail solidly dark (often barred basally on Herring); A1 scapulars tend to have dark centers or be diffusely patterned, lacking bold bars common on Herring.

CONTINUE PART 4: FIELD IDENTIFICATION - SECOND & THIRD CYCLE

East coast birds

West coast birds