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Odd Lesser Black-backed type gull today (12 Jan.), eastern Pennsylvania, USA (1 Viewer)

birdmeister

Well-known member
United States
Hello all,

I observed an odd gull this afternoon at my local reservoir, unfortunately in fairly poor light with the setting sun. Hopefully I'll get back tomorrow and it will still be there.
Here are the comments I entered after arriving home:

"Flew in during late afternoon, arriving slowly like LBBG and Herring Gulls do (unlike Ring-billed's twists and turns). Flight views once I realized it was different were brief, but I thought it had a pale window near the wingtips, similar to those of other immature gulls.

When perched, the bird looked very "frosty" and pale above. It had an odd pale wing panel of sorts on the folded wing. A few features almost suggested Iceland Gull to me, but other features clearly went against that. Size-wise it was similar to LBBG, smaller than Herring. I thought it had a more rounded head like Iceland, unlike the flat and angular heads of the adult and young LBBGs. To my eye, it looked like there were some very pale gray mantle feathers coming in, which would go totally against LBBG. However, the wingtips looked very dark, going strongly against Iceland Gull. When I really zoomed in on photos, it appears there may be slightly paler spots, but these are not claimable based on the lighting and photos. Another feature that I thought went against Iceland was the very bold dark chevrons/anchor marks on the scapulars/mantle."


My guess is that the easiest explanation for this bird is a paler-than-normal LBBG. However, I found it hard to shake the few Iceland features that I seemed to get while watching the bird.

I'll attach multiple photos below, as well as the palest immature LBBG that I could find among 45 or so that were present. I suspect that aging this mystery gull is very important, which I'm not good at. Some images provide direct head/bill shape comparison to both Herring and LBBG, while the 5th image in this post was under a different exposure, one that better illustrated how pale this bird looked in the field.
 

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birdmeister

Well-known member
United States
More pictures below, mostly for comparison between Herring and LBBG.
 

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birdmeister

Well-known member
United States
Finally, the palest LBBG I could find for comparison. Lighting conditions were similar.
 

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HeadWest

Well-known member
My thought would be a somewhat odd herring gull, with weird paling in the coverts. Probably a female given the Iceland-like bill size and proportions. I think the lighter mantle feathers molting in point away from LBBG, as does a window in the primaries. An Iceland would show some amount of pale edges to the primary tips.
 

lou salomon

the birdonist
hi birdmeister,

your bird is an american herring gull. it has a slight deficiency of melanin accounting for the bleached mid wing panel (usually seen only in late spring). structurally this is a compact bird but with longish wings (small ind. of large gull species have proportionally longer wings). the overall smudgy/plain dark marked body and hindneck with a slightly paler head as well as the pattern of scapulars is in line with smithsonianus but off for LBBG. and you also noted one of the main differences: paler inner primaries forming a 'window'.
 

birdmeister

Well-known member
United States
Thank you very much, Lou and HeadWest! Thanks especially for the detailed comments. I ran it by some other folks, too, and at least one other said that the scapular pattern really fit only (American) Herring Gull.
 

tom baxter

Well-known member
hi birdmeister,

your bird is an american herring gull. it has a slight deficiency of melanin accounting for the bleached mid wing panel (usually seen only in late spring). structurally this is a compact bird but with longish wings (small ind. of large gull species have proportionally longer wings). the overall smudgy/plain dark marked body and hindneck with a slightly paler head as well as the pattern of scapulars is in line with smithsonianus but off for LBBG. and you also noted one of the main differences: paler inner primaries forming a 'window'.
It also has a tiny black bill and pretty round head. Why not Thayer’s? Its head and bill looks structurally unlike any herring gulls I’ve seen, whether personally or reported in online groups.
 

lou salomon

the birdonist
1st cycle herring gulls are highly variable. this bird cannot be a thayer's gull because of the large amount of replaced scapulars and their pattern with mostly sharp contrasting black transversal bars to their centers. the general look of this 1st cycle gull suggests it is from the great lakes population, in which they tend to look paler and more contrasting.
 

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