January 28, 2005
Gulls, gulls, gulls
Yesterday I spent an educational morning with gull afficionado and fellow Brit Jon King at the Yolo County Landfill. Although we were unable to relocate the presumed Kumlien's Gull found by Jon last weekend, we saw a good selection of the common and scarcer gulls, plus a couple of interesting hybrids. We had great views of several Thayer's Gulls, including this adult - note the dark eye, rounded head shape, greenish tinge to the base of the bill, large white primary spots and deep pink legs.
Here's a nice comparison of an adult American Herring Gull (left) and Thayer's Gull (right) - again note differences in eye and leg colour, head shape and the extent of white in the primaries. The chocolate-coloured gull in the foreground is a first-winter Thayer's.
I'm less sure about this gull. Given the extent of white in the wingtips and the mantle colour, I'd go for Thayer's. However, the wingtip pattern is like adult Thayer's while the bill pattern would be more characteristic of a 3rd-winter. Any thoughts on this bird appreciated! Footnote: Jon comments that the structure and eye colour are wrong for Thayer's, and suspects it could be a Herring x Glaucous-winged hybrid.
There were also many Glaucous-winged Gulls on show, including this fine second-winter.
Somewhat further away was this dark first-winter Western Gull (note all-dark centres to the tertials).
This adult Mew Gull was the sole sighting of the day.
And now to the hybrids. The long, pink-based bill and frosty plumage of this bird point towards hybrid Glaucous x Herring, aka Nelson's Gull.
Jon's opinion of this bird was hybrid Glaucous-winged x Western Gull, presumably based on the extent of pale feathering in the scapulars and greater coverts.
Am hopefully slightly more clued up on these species now - would be nice to have a Yolo Slaty-backed Gull to practise on!