ML645904027

Observation details

While scanning the roosting flock of gulls on the western Terrace, I (Nathan) stumbled upon a large, dark-backed gull just in front of us, similar in size and shape to a Western. I immediately noticed the legs and bill, primarily struck by the color of both being yellow. I let Jim know, and while he watched the gull, I took some photos as it stood in front of us and as it flew off deeper into the roost. We then moved on as to not flush the entire group. We notified Nick and Max, who then went to search for the gull unsuccessfully. After finishing the count, we took a look at the photos and realized the gull may well be a Yellow-footed. Bright yellow legs and feet, massive, bright yellow bill that had a base about the same width as the rest of it, relatively pale eye (dark conditions lead to dilated pupils), yellowish orbital ring and gape all looked good for one. Upon trying to discern it from a WEGU in a state of hormone overload (rare at this time of year), we looked at feather condition (thanks to Amar’s Gull Guide for reference). The apical spots to the middle primaries (P5-6) were heavily worn (P4 as well), indicating that they were molted in some time ago. The outer primary apical spots are still pretty fresh (P8-10), with intermediate wear on P7. All adult WEGU at this time are still completing their primary molt and have very fresh apical spots throughout the primaries. This is the only large, dark-backed, adult Larus on island that we have seen with this primary condition during the last few days. With all of this taken into consideration, we feel comfortable identifying this gull as the islands first record of Yellow-footed Gull. Note: Image editing was only performed to bring exposure up as the originals were a tad dark for the average viewing screen.