Idaho Bird Records Committee Rarities Report Form
Rare Bird Report #: 18-B-07
Species: Glaucous Gull
Reporter: Cliff Weisse, 4125 Beaver Springs Rd., Island Park, ID 83429, 208-558-7789, cliffandlisa@octobersetters.com
Other Observers: none
Date of Observation: 2/18/2007
Date Report Prepared: 2/25/2007
Number seen: 1
Locality of Observation: CJ Strike Reservoir, near the end of the road at Jack’s Creek then at Cottonwood access.
Habitat: Reservoir
Conditions: Overcast with strong wind. I had to stand behind the truck to block the wind enough for good scope views. Distance 150-200 yards (estimated) with Swarovski 80 mm HD scope w/60x eyepiece.
Did you take notes…no
Did you consult a field guide or other reference work?
no
What guide or reference did you consult?
Description: Large first winter gull with fairly heavy body but not as deep or chesty as the 1st winter Glaucous-winged Gull it was associating with in direct comparison. Obviously larger than all seven Herring Gulls present in close proximity and about the same size as a 1st winter Glaucous-winged Gull also in close proximity.
-Whitish plumage was lightly marked with tan creating off-white appearance.
-Wing coverts and scapulars lightly marked with tan but exact pattern not noted.
-Bill long (longer than Herring Gulls present) with parallel edges and insignificant gonydeal bulge. Sharply bicolored, bright pink base with sharply demarcated jet black tip. Extreme tip of bill was paling and appeared flesh colored, not sharply demarcated but rather fading from black to flesh.
-Iris dark
-In flight wings appeared whitish from below.
-Primaries clean white with no discernable markings
-Legs pink
-Head whitish
-Tail very pale grayish, not appearing as white as primaries in flight.
Although the bill was paling at the tip I’m sure this was a first winter bird based on the lack of gray feather in the mantle and obvious tan markings on the wing coverts.
Behavior: Perched on small mud island picking at floatsam. Several times it chased nearby Herring Gulls off a choice piece of food and stole it. Later I saw this individual flying west towards the dam at Cottonwood Access and 1.5 miles from original location.
How and when did you positively identify the bird, and what clinched the identification for you? I recognized this bird as a Glaucous Gull instantly. The overall whitish appearance and bicolored bill combined with its large size are unique to this species.
How did you eliminate similar species, and what were they? The only real contender is Iceland Gull. All other species of large gull are eliminated by the white primaries. Iceland is eliminated by large size, long bill, sharply bicolored bill, and light (tan) markings on wing coverts. Icelands have darker brown marking on the wing coverts that are limited producing an overall pale appearance and typically do not show bicolored bill pattern until second winter.
Experience with this species: I’ve seen maybe 9 Glaucous Gulls previously.
General experience birding: 14 years
Were photo(s), video, and/or audio obtained by you? no