Date: 12/21/18 5:29 pm From: David Ely <mountainplover...> Subject: [cobirds] Slaty-backed gulls and other gulls at Larimer Landfill today.
Many of us stood vigil hoping for the gyrfalcon to make an appearance this morning at the Larimer County Landfill (no luck on that front for our group). The gulling was a quite good alternative from 8-11AM when Matt Hofeditz, David Leatherman, and I where there. We were able to see the continuing first winter glaucous gull and glaucous-winged gull from Trilby Road in very good light and still air. We also noted many Iceland (Thayer's) gulls and lesser black-backed gulls among the numerous ringers and herring gulls. We also saw a 1st winter great black-backed gull and what I chalked up, at the time, to be a near adult great black-backed gull. The later bird was observed both on the ground for a short period of time and then flying. At the time I initially thought that the bird sure looked like a slaty-backed gull. I admit that I sort of lost my train of thought on this bird as I detected the glaucous-winged gull in the same field of view and re-directed my attention to it. When I arrived home I touched base with others who believed they had seen a slaty-backed gull in the same plumage and matching the description of the bird we saw this morning. They had seen this bird 3 days ago. We concluded that this very, very likely an adult or near adult slaty-backed gull. I have copied my checklist below in which there are additional details. I can try to provide more information later or upon request. I'm sure everyone is hustling ahead of Christmas like I am and I wanted to get the word out.