Dinsmore & Silcock, "First Record of a Ross' Gull for Nebraska," from Nebraska Bird Review (June 1993) 61(2).
On 17 December, 1992, we observed a Ross' Gull in second-winter plumage at Sutherland Reservoir, Lincoln County. We studied the bird in detail from 7:35-10.00 a.m. and again from 11:15 a.m.-1:00 p.m. CST as it fed with several Bonaparte's Gulls at the outlet between the cooling pond and the reservoir. The Ross' Gull remained at this location through 28 December and was seen by many birders from around the Midwest.
During all of our observations, the small size, dark underwings, and wedge-shaped tail set this bird apart from the Bonaparte's Gulls. At first, we overlooked the tail shape and tentatively identified the bird as a Little Gull. However, after studying the bird in greater detail, we noted the wedge-shaped tail and agreed that it was indeed a Ross' Gull in second-winter plumage.
We estimated that the Ross' Gull was about 10% smaller than a Bonaparte's Gull, and had proportionately longer wings, a smaller head, and larger eyes. It had a buoyant flight, and often hovered over the water as it fed on small fish. The undersides of the flight feathers were dark gray, similar to the appearance of the underwing of an adult Little Gull. The axillars and wing linings were white. The upperwing was mostly pale gray, with clear remnants of a dark carpal bar. The carpal bar was black, and appeared as a series of spots across the secondary coverts, with a larger black spot at the base of the primaries. There was also a very broad, white trailing edge to the flight feathers, especially along the inner primaries. The mantle was also pale gray, the same color as the upperwing. The head was white except for the hint of a black collar, which appeared as a darker spot behind each eye, connected by a faint, dark line across the back of the neck.
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