Date: 11/26/17 8:23 pm From: NICHOLAS KOMAR <quetzal65...> Subject: [cobirds] Gulls near Wellington (Larimer County) - possible Slaty-backed Gull
A large communal gull roost is currently forming each night at Cobb Lake southeast of Wellington, best viewed from CR56 east of Interstate 25 in Larimer County. I believe between 2000 and 5000 gulls utilize the roost. A subset stages just before sunset near the lake's north shore and can be well viewed through a telescope from CR56 between 4 and 4:30 pm. Most of the gulls are California, but large numbers of Ring-billed and Herring are also present. Today, there was a large white-winged gull that appeared to be a first-cycle Glaucous Gull. Both yesterday and today, an adult blackish-backed gull was present. This gull was the size of Herring Gull, with short wings (like Herring), a yellow bill with small red gonydeal spot, and a very large head. These features are consistent with Slaty-backed Gull. Hopefully I or someone else will get photos that will help identify this bird.