Gulls at Panamá Viejo

Today Rosabel and Karl Kaufmann and Darién and Camilo Montañez stopped by the Bohío Turístico at noon, where the gulls forage in the mudflats at low tide. Try as we did, we did not see the Gray Gull, but had an interesting sighting anyways. Standing in the mud next to a few Laughing Gulls was a gull of about the same size, but with bright yellow-orange bill and legs. The back and wings were uniform gray and the head and underparts were white. The ear-coverts were dark gray, and the nape was also gray, ligter than the back. The wing-tips appeared to be black, as was the tail. So, in fewer words, the plumage was that of a Laughing Gull in winter. When the bird took flight the wing pattern was observed to be, also, like the one a Laughing Gull. So, our best guess is that this was an aberrant individual. In fact Peter Harrison's "Seabirds, an identification guide", says that the Laughing Gull has been "recorded with anomalous bare parts colours".
So now you have two reasons to go to Panamá Viejo. This individual should be as easy to pick out from a large flock of gulls, its bill being so brightly colored. So if you think you have a Gray-hooded Gull check the wing pattern extra carefully.