ML287627841

Age and sex

Immature Unknown sex - 1

Observation details

Found by John Harris. Second-cycle. (I initially called it a first-cycle, having assumed that a second-cycle bird would have some adult-like gray mantle feathers as in other large gulls—thanks to Rudyard Wallen for the correction, and for lots of additional helpful info!) John has much better photos, taken when he saw the bird on the posts in the southwest corner of Salt Pond A1. After I ran into him and he showed me the photos, we both tried to relocate the bird, and found it resting with other gulls on the mud flats of the main part of the Coast Casey Forebay. I got decent binocular views here for a few minutes, and John watched it in its scope, before a Bald Eagle flew by and flushed all the birds in the forebay, at which point we lost the Glaucous Gull in the shuffle. Most of the gulls headed north over the salt ponds or east toward Shoreline Lake. Some circled back to the forebay a minute later, but the Glaucous was not among them, and my subsequent attempts to relocate it in the area were unsuccessful. During the time I saw it, I noted its very pale whitish-tan appearance overall, apparently including its wingtips, though I never got a good view of its spread wings. At rest, its primaries appeared no darker than the rest of its body, as the photos show. The bill appeared pinkish in the field with a dark tip. Photos show that the bill is a washed-out, orangish shade of pink, paler than the legs. This seems consistent with Macaulay Library photos of second-cycle Glaucous and with Sibley’s illustration. Birds of the World says, “by second winter black on bill tip less extensive and base beginning to show yellowish or yellowish flesh”, as the bill coloration gradually transitions toward that of an adult. John Harris’s photos (https://ebird.org/checklist/S77406624) are much better than mine, and they show that this bird has a yellow iris, another match for a second-cycle bird, which I didn’t notice in the field. The photos also show a small pale area at the very tip of the bill. I haven’t found a whole lot of information about hybrids, but to my relatively untrained eye, I don’t see any features on this bird suggestive of Glaucous-winged or Herring, and a quick look at some Macaulay Library photos of Glaucous x Herring and Glaucous-winged x Glaucous doesn’t show me anything that seems like a match. I don't have any useful photos aside from the one attached, as all the others either look almost identical to this one or are similar but with the bird's head hidden. The other gulls in the photo are an adult Ring-billed on the left and three adult Californias on the right.

Additional species

• California Gull Larus californicus
• Ring-billed Gull Larus delawarensis
• American Coot Fulica americana

Technical information

Model

Canon PowerShot SX620 HS

ISO

1250

Focal length

112.5 mm

Flash

Flash did not fire

f-stop

f/6.6

Shutter speed

1/1000 sec

Dimensions

591 pixels x 443 pixels

Original file size

80.36 KB