a white-winged gull

There was a white-winged gull at Cupsogue this morning (see photos below by Byron Young and Eileen Schwinn). This is presumably the same bird that was seen the other day and was identified as a Glaucous Gull. But is it a Glaucous Gull? As can be seen from these photos (both made this morning), the bird is noticeably smaller than the Great Black-backs it is hanging out with. More to the point, it has the rounded head, large eye and long primaries of an Iceland Gull, not the beady-eyed, large-headed, sloped-forehead, bull-necked, broad-chested, powerful look of a Glaucous. Glaucous Gulls can look as large as a Black-back and match them in that king-of-the-sand-flat look and behavior. Our bird was meek and timid; it slunk away and pecked at a spider crab at the side of the island with its head down. It had the look of a mild-mannered Ring-billed Gull next to a Herring, not a Herring Gull next to a Black-backed.

You can't ID these birds by color and even size can be tricky. Take a look at Howell/Dunn "Gulls of the Americas" and you'll see why the issue is not always so clear-cut! All these gulls can actually overlap quite a bit in size (Iceland: 19-24.5", Glaucous: 21.5-29", Great Black-backed: 25-31" according to Howell/Dunn). One feature in favor of Glaucous might be the length of its bill and the bill's clean ,two-toned coloration. But a so-called second cycle Kumlien's Gull (a subspecies of Iceland Gull and a potential split) can have a two-toned bill and it's not even clear that other forms of the Iceland Gull might not have the same. The coloration of the plumage and the soft parts on all these birds is very variable. The crucial issue has to be structure and I think this bird lacks the massive structure of a Glaucous Gull. Pictures below.

A couple of additional notes. Some thought the bird was lame but that didn't seem so obvious to me. Iceland Gulls are rare in the summer but not unknown (Glaucous Gull is even rarer but also not unknown at this time of the year). Finally, it should be mentioned that the unlikely Kumlien's Gull (if that's what it is) would be a good bird for Long Island at any time of the year!

This morning's expedition was an ELIAS walk led by Eileen Schwinn. It was a hot, heat-stroke-inducing morning and, as always, Cupsogue and Pike's Beach were popular with weekenders -- even in the middle of a massive, end-of-the-world heat dome. But there was a good turnout of birders and lots of birds to be seen, notably terns: Black Terns including two or three still in breeding plumage; a flying Roseate Tern; Forster's Terns including fresh juveniles (locally born?) on the island opposite the Pike's viewing platform; three Royal Terns (two adults and a youngster also on the island opposite the Pike's platform); small numbers of Least Terns (this species is at a low ebb) and many Common Terns. Also Black Skimmer. Among the shore birds: a dozen Red Knots, hundreds of Short-billed Dowitchers, some possible Long-billed Dowitchers, hundreds of Least Sandpipers, small numbers of other common shore birds -- Semipalmated and Black-bellied Plovers, Semipalmated Sandpipers, White-rumped Sandpipers (by sound), a few Ruddy Turnstones and Sanderlings, and the usual locals (Am Oystercatcher, Piping Plover, Willet). Boat-tailed Grackles in all sizes and shapes were everywhere.

Eric Salzman