OK, I admit it. I often don’t have the patience to scan through large flocks of gulls to find the “oddball”, the one that ISN’T the seemingly ever-present Ring-billed Gull (here in South Dakota). Sometimes, however, you see something that’s clearly so different than you can’t help but notice. That was the case yesterday near Pierre, South Dakota, when I saw a large, nearly all white gull sitting on the ice. My first thought when seeing the bird from a distance…Iceland Gull, since recent bird reports had frequently mentioned an Iceland Gull being seen in the area. At first glance, that seemed to “fit”. However, as one who isn’t well-versed in the dark art (I’m think of you Ricky Olson!!) of multi-age gull discrimination…I wasn’t sure. It wasn’t until I got home, downloaded the photos, and did some sleuthing where I think I can safely call this an immature (probably 2nd winter), quite pale Glaucous Gull. Why?
Immature Glaucous and Iceland Gulls both share some characteristics that were evident in this bird. 1) Pale overall, including pale wingtips without markings. 2) two-toned bill. 3) pink legs. However, when looking at Sibley’s and online resources, it’s clear the bird has characteristics of a Glaucous Gull. First…the bird’s size. There were a handful of Ring-billed Gulls around, and this bird was clearly larger. Much larger. Iceland Gulls are larger than Ring-billeds, but Glaucous Gulls are MUCH larger. With the distance between the Ring-billed Gulls and this gull, it was a bit difficult to judge, but it really did look a much, much larger bird than the Ring-billed Gulls.
Secondly…the head. From this excellent site (South Dublin Birds), it’s noted Glaucous Gulls have a large, flat-topped head, while Iceland Gulls have a more delicate looking, rounded head. This bird clearly has the head shape of a Glaucous. Also…that site is the only one I found that notes a “tertial step”…a clear angle where the tertial feathers on wings meet the primaries when the wing is folded as in the first photo below. Here, you definitely see a clear “step” down where the tertials meet the primaries. Finally, the bill. Young Glaucous and Iceland Gulls both may share a two-toned bill such as this, but the Glaucous Gull has a heavy, longer bill, with parallel top and bottom edges. The Iceland Gull has a much more delicate and smaller looking bill. The bill on this bird is quite large and shaped as a Glaucous.
So my final call…a first- or second-winter (probably second), very pale Glaucous Gull. Darker juveniles often have a lot of brownish speckling. This bird has a very small amount of that, primarily near the tail. Given that Glaucous Gulls gradually lose that speckling and it’s mostly gone by the third year, my guess is its a second-year bird that’s lost most of the speckling. Third winter birds generally already have the pale gray mantle of an adult Glaucous Gull. This bird clearly doesn’t have that yet, so it can’t be a 3rd year or adult bird.
In short…the bird looks very similar to the Sibley drawing of a 2nd-winter Glaucous Gull (Page 220 of my Sibley’s guide!).
There…that wasn’t so painful! And it was kind of an interesting challenge to ID. Perhaps next time I come across a flock of gulls, I’ll pay a little more attention and do some similar sleuthing!