ML313096101

Age

Not specified

Sex

Not specified

Observation details

*rare, adult on beach at south end of Gulick Drive. In large mixed gull flock composed primarily of Lesser Black-backed and Ring-billed. Initially caught my eye as the only adult “Herring” in the flock, but it quickly became apparent that this bird was distinctly smaller than the nearby Lessers. Further study revealed this to be an adult Iceland Gull, albeit a very dark-winged individual. It was content to forage as we watched it for ten or so minutes, swimming in the surf and preening on the beach. The gull flock flushed after this time, and the bird was not relocated after it flew north. We viewed this bird under optimal lighting conditions (high overcast, creating bright but muted lighting), and while the mantle was certainly paler than that of the Lessers, it was only slightly more so than that of the adult Ring-billed. Structure was one of the key traits that separated this from Herring; it was dove-headed, with a small bill, and rather short legs creating an almost dumpy appearance. Wingtips clearly black but with a distinctive paler underside, visible on the folded wing on the opposite side of the bird from us. Primary mirrors seemed perhaps slightly larger than those of Herring, with a visible dark outer web on P4. Nape lightly streaked. Bill an even bright yellow with red gonys; dusky iris; pale pink legs. In all features, this bird would seemingly fall within variation between Thayer’s or extremely dark-winged Kumlien’s. Unfortunately flight shots were not obtained, and so the diagnostic Thayer’s pattern on the spread wingtip was not noticed. While I think the bird probably falls closer to Thayer’s, it might not be possible to claim definitively without the wingtips fully visible for study.

Technical information

Model

Canon EOS 7D Mark II

Lens

EF400mm f/5.6L USM

ISO

200

Focal length

400 mm

Flash

Flash did not fire

f-stop

f/7.1

Shutter speed

1/1250 sec

Dimensions

2600 pixels x 1733 pixels

Original file size

1.92 MB