Date: 10/21/17 9:59 pm From: Nicholas Komar <quetzal65...> Subject: [cobirds] Larimer County gulls (Alberta Gull)
Lake Loveland is currently a great spot to study gulls. This morning, a flock of approximately 200 birds were resting in the NW corner, with excellent viewing from the swim beach (good lighting). About 3/4 were California Gulls and 1/4 were Ring-billed Gulls. I counted 9 adult Lesser Black-backed Gulls! There were no Herring Gulls today, but a few were present there recently. Among the numerous Cal Gulls were 2 (possibly 3) "albertaensis" subspecies (aka Alberta Gull), which is quite uncommon in Colorado. For those interested I've included a photo of the 2 Alberta Gulls and the description I submitted with my eBird checklist.
Lastly, this morning I saw my FOS (first of season) Bonaparte's Gulls at Buckingham Lake in SW Loveland.
Description of Alberta Gull:
At least two, possibly three birds, all adults. Loafing among the gull flock in the NW corner opposite the swim beach. First impression was Herring Gull due to larger size and paler gray mantle relative to the numerous californicus Cal Gulls. However, unlike Herring, these birds had dark irides, black/red gonydeal spots, bluish legs, and extensive black in wingtips, all field marks for Cal Gull. Finally, spread wing photo shows a large white mirror extending to the tip of P10, a field mark for albertaensis.