The thin bill eliminates Western, Yellow-footed, Kelp, Slaty-backed, Glaucous-winged, and Greater Black-backed Gulls. The two-toned bill eliminates first winter Lesser Black-backed and 1st-winter Thayer’s Gulls, while the dark brown plumage and dark tertials eliminate Glaucous and Iceland Gull. The two-toned bill and somewhat thin bill should eliminate 1st winter Herring Gull (which should have an all-dark bill), although if we weren’t made aware of the time of year this photograph was taken, we would have to consider 1st summer Herring Gull, which could have a two-toned bill. However, this bird has dark tertials/secondaries and dark greater coverts (although the latter is not as dark as the former), the former, in particular, contrasting with the rest of the wing. While the tertials on 1st winter and 1st summer Herring Gull are dark, they tend not to be as constrastingly dark as in California Gull. The long-winged appearance of this bird also does not fit Herring, which should have a somewhat shorter extension of the primaries beyond the tail. This leaves us with Ring-Billed, Mew (Common), California, and Black-tailed Gull, all of which have two-tone bills during the 1st year. The brown wings and in particular the brown greater covert (with pale edges) eliminate 1st year Mew (Common) and Ring-billed Gulls because these latter two species would have extensive gray in the coverts. In addition, the bill appears too long for either Mew or Ring-billed.
A number of superficial features are reminiscent of 1st-winter Black-tailed Gull, and indeed this species garnered more than 50% of the votes. The long and two-toned bill, somewhat angular head, and overall brown coloration resemble 1st-winter Black-tailed. However, the following marks on this bird are inconsistent with Black-tailed: brownish belly and undertail coverts, barred flanks and sides, and paler wing panel contrasting with dark greater coverts and tertials/secondaries. 1st-year Black-tailed has pale to white undertail coverts and flanks, no barring on underparts (more uniformly and smoothly washed), and more uniformly colored wings. The greater coverts on this bird appear to be pale-tipped, a feature not so prevalent on Black-tailed. Instead, all of these features are consistent with 1st year California Gull. The angular and flat-topped appearance of this bird’s head is not typical of California Gull, but it may be worth noting that the photograph was taken on a very windy day, so that the bird’s posture and head shape may be an artifact of hunching in the wind. This bird is indeed a 1st-winter California Gull. It was photographed at Drakes Beach on Point Reyes Peninsula, California.
The identity of the adult gull pictured above will probably remain unknown, given that we couldn’t figure out the color of the legs (guesses ranged from yellow to orange to pink!). This leaves us with Herring, California, Western, Glaucous-winged, Western X Glaucous-winged, or Slaty-backed. Based on range and the fact that the photographer didn’t notice a mega-rarity while he was there, the last option is unlikely. The extremely dark primaries rule out Glaucous-winged Gull. The seemingly dark mantle color appears to rule out Herring. This leaves us with California, Western, and Western X Glaucous-winged Gulls. Assuming that the overall gizz on this bird is not an artifact of windy conditions, the somewhat shorter primary extension, compared to that of the California Gull in the foreground, is inconsistent with California. In addition, this bird appears noticeably larger than the bird in the foreground. This leaves us with Western Gull or Western X Glaucous-winged Gull. We leave the identity of this adult gull at that, but welcome further discussions on our bulletin board.
Cin-Ty Lee
Unfortunately, a few features may also hint at Least Flycatcher, namely, the pale lower mandible, somewhat pale lores, and large-headed appearance. However, Least often tends to have a messier eyering (particularly behind the eye) and may have a slightly dusky tip. In the field, it is likely that we could have narrowed our ID further using voice. This photo illustrates how difficult it is to ID empidonaxes, particularly when given only one photo. We continue to welcome comments or further discussion on the identification of this flycatcher.
George has lots more great photos at his website.