Mystery Gull at Huron, Erie County, Ohio 01/29/2002

Species: glaucous-winged gull (Larus glaucescens)
Date Observed: 01/29/2002
Date of this write-up: 01/29/2002 through 02/05/2002
Observer's name: Greg Miller
Observer's E-mail address: hawkowl@yahoo.com
Location (county, city, place, etc.): Erie County. Huron, Ohio. South end of the Huron Pier on the stone piles on the East side of the pier.
Number, Sex and Age of Birds(s): 1 individual. Given it's size (slightly smaller than most [but not all] herring gulls) and the extreme variability of the sexual dimorphism in glaucous-winged gulls, I'd guess this individual to be a female. Judging from it's relatively clean plumage, I give my vote for an adult gull in basic plumage.

Decription--Describe the entire bird, not just key field marks:
Unless noted otherwise, all references to herring gulls in this text are for Larus argentatus smithsonianus.

BILL: About the length of nearby herring gulls, but vertically thicker, especially at the gonydeal angle. Overall color of bill was a warmer yellow than adjacent ring-billed and herring gulls. This individual had a small red gony spot. Black smudges were apparent on both the upper (very thin) and lower mandibles. The blackish coloration on the lower mandible was located adjacent distally (toward the tip of the bill) to the red gony spot. The black on the upper mandible was directly above the black on the lower mandible and thinned as it approached the culmen.

EYES: Decidely dark as compared to surrounding herring and ring-billed gulls. This individual was observed in a number of different head positions so as to prove whether or not eye color was dark or light. Eyes appeared slightly smaller in proportion to head size than adjacent herring gulls. No color on orbital rings were observed.

HEAD: White with gray smudges (not streaks or bars). Throat white. Smallest spots of gray on forhead and crown. Larger splotches on nape and sides of neck. A larger gray smudge encompassed the eye, back into the auriculars. Head shape more nearly approached that of surrounding herring gulls than most glaucous-wingeds I've seen (although it was not out of the range of variation that I have experienced either). The forehead slope was greater on this individual than that of the herring gulls and the overall "blockiness" of the herring gulls was more pronounced than on this bird (slightly more rounded).

UNDERPARTS: Chest, belly, flanks, and undertail coverts completely white and unmarked. Structurally, this individual was "chestier" and maybe slightly larger-bellied than surrounding herring gulls, giving it a stockier appearance (although it was smaller in overall size than most of the nearby herring gulls).

LEGS: Apparently pinkish gray. Given the overcast skies, the distance to the bird (roughly 150 yards), and it's position atop one of the large stone piles, the bird's legs were backlit and difficult determine a good color. Compared to herring gulls next to this bird, however, the legs appeared decidely duller and more grayish. When the bird lifted it's leg, the webbing was quite pink (maybe even more so than herring gulls).

TAIL: Shorter proportionally compared to herring gulls next to it. Unmarked. Pure white.

UPPERPARTS: Mantle was an even, medium gray. This gray was slightly darker than any adult herring gull, but was not nearly as dark as an adult basic lesser black-backed gull (Larus fuscus graellsii)--also seen the same day at the Huron Pier, but on the West side of the pier. In my opinion, the medium gray was just shy of the darkness of a laughing gull. No off-color feathering was noted in either the wings or back, leading me to believe this is an adult bird. Additionally, the wing coverts and tertials of this bird at rest were all of the same uniform medium gray color. White scapular and tertial crescents were present and were as wide proportionally as the very widest crescents on the surrounding herring gulls. The primary extension was noteably shorter than the herring gulls, with the end of the tail being just shy of the apical spot on P9 on the standing bird. The primaries themselves were a shade darker than the upperparts of this bird. This darker gray approximates the mantle color of a laughing gull. There is not much contrast between the gray of the back and wings and the primary color. It is definitely not black or even dark gray. Up to five white, apical spots (tips of the primaries) can be seen on the standing bird, although the fifth spot is visible only some of the time. The white, apical spots appear to be a tad larger proportionally than adjacent herring gulls. As the bird preened, I noted the undersides of P9 and P10. The undersides of P9 and P10 are pale, dishwater gray (lighter than adult herring gull mantle). No dark trailing edge was apparent at all. A large mirror exists on P10. The location of this mirror was approximately 1/3 of the bill length up from the tip of the primary. The mirror did not reach the tip. The mirror on P9 was about the same distance fromt the tip of the primary, but was very small (a little larger than eye-size). The bird was not observed in flight, nor did it conveniently fully stretch it's wings. Unfortunately, the remaining primary patterns were not noted. Additionally, the remaining underside of the wing was missed as well.

Behavior: This bird was more aggressive than many herring gulls. It would stand atop of the large stone pile and maintain its position most of the time when other ring-billed and herring gulls approached it. Strangely, it did not spread its wings when other gulls approached it for position, but it would simply stretch its neck out and open its bill wide. This did appear to be quite effective. It did give away position to great black-backed gulls, but would not fly, but would walk down the East side of the stone pile. The gull would then be out of view for up to five minutes, but then would reappear nearby, atop the stone pile again. The bird spent most of its time standing and sometimes preening. It was never observed in flight.

Viewing Conditions (weather, time, and optics): The bird was observed [almost constantly] from 10:00am until noon. Skies were overcast the entire time. Light rain was encountered a couple times during this period. Wind was negligible at 5-10mph from the Southwest, but felt cold as the air was full of moisture. Temperatures were in the mid-40's F at the lakefront, even though inland temperatures were in the 60's F. I viewed this bird through both binoculars (Zeiss 10x40) and telescope (Kowa TSN 4 with 20-60x zoom). I observed the bird from the cement walkway at the South end of the Huron Pier. The bird was on the giant stone piles to the East at roughly 150 yards. Sunlight was not a problem, but the overcast skies never afforded me views of the gull in good sunlight either. Photos were not obtained as I did not have a camera and the bird was distant enough that Dan Sander's videos will be inadequate. Attempts to video through a telescope were in vain.

Observer Experience (with this species and in general): I have more than 35 years of birding experience overall and have birded in all 50 states. I first observed glaucous-winged gulls in Oregon in 1970. I have seen this species in California, Oregon, Washington, British Columbia, Alaska, and the Aleutians. My most recent experience is with glaucous-winged gulls is on Attu, Alaska in September of 2000 and in California in January of 2000.

Other Observers: Dan Sanders, Doreene Linzell, Gretchen Fluke, Marje Baughman

Additional Comments: Other species considered included:

THAYER'S GULL: thayer's gulls have dark eyes like glaucous-winged gulls, but their mantle color is paler and their primaries (on the upperwing) are black instead of gray. Overall size of thayer's gull is smaller than the Huron gull. The thayer's also has a proportionally smaller bill.

VEGA (HERRING) GULL: vegae gulls have dark eyes and mantle color certainly is similar to that of the Huron bird. The upperwing primaries on vegae gulls, however, is black and not medium gray. Additionally the large mirror on P10 of the Huron bird is inconsistent with any subspecies of herring gull. (I have some experience with vegae gulls on Gambell, Alaska, in May, 1998).

CALIFORNIA GULL: Although mantle coloration and dark eye both fit, california gull also has black primaries (upperwing) and the mirror patterns in the outer primaries is inconsistent with the Huron gull.

LESSER BLACK-BACKED GULL (Larus fuscus graellsii): Darker mantle, black upperwing primaries, and yellow legs rule out this species.

YELLOW-LEGGED GULL: Mantle color is OK, but light eye, black upperwing primaries, yellow legs, and flat/square-headed posture of yellow-legged gull do not fit the Huron gull.

Dark-mantled gulls: All ruled out because the mantle colors are too dark for the Huron bird and all have black upperwing primaries.

White-winged gulls: All ruled out because they lack enough darkness [if any] in the primaries and have mantles that are too light.

Other considerations: Glaucous-winged gulls are extremely promiscuous and commonly hybridize with other gulls. I only have experience with the glaucous-winged gull x western gull complex on the West Coast. Although birds of this combination allegedly can take on the attributes of either parent, I have never seen a hybrid that took on most of the components of one parent. In my limited experience, hybrid glaucous-winged gulls usually take on an identifiable mix when hybridizing with western gulls, especially noted mantle color, and in primary coloration and patterning. Often the bill shape on this hybrid is pretty obvious when it takes on the characteristics of the western gull (the bill appears larger and bulkier). As for the glaucous-winged gull x herring complex, I have no experience. Here, I would note that mantle, upperwing and underwing primary coloration, primary patterning, primary projection, chest/belly posture and eye color all belong to glaucous-winged gull. Bill and head shape could possibly be intermediate, although neither one falls outside the variability of either glaucous-winged gull or herring gull. Additionally, this bird possesses indistinct splotching on the head and neck (unlike the typical barring of many glaucous-wingeds or the typical streaking of most herrings) and is whiter headed than either "typical" glaucous-winged gull or herring gull at this time of year (mid-Winter). Even so, this amount of "whiteness" is well within the range of mid-Winter basic plumage of either species. I might entertain a herring gull x iceland gull hybrid, but the primary pattern fits neither parent. Finally, I believe that this bird is either a good glaucous-winged gull or at the very least, a glaucous-winged gull x herring gull hybrid which approaches all the characteristics of the glaucous-winged gull.

Questions: Of the vagrant glaucous-winged gulls that have occurred in the Great Lakes region (Minnesota, Wisconsin, and Illinois), how many glaucous-winged gull hybrids have been found by comparison? Is it more? Less? The same? And what type of hybrids have been found? Are they all glaucous-winged gull x herring gull hybrids?