Rare Bird Report #: 6-B-07

Idaho Bird Records Committee Rarities Report Form

Species: Glaucous-winged Gull – a 1^st winter bird

Reporter: Jay Carlisle

6105 Kirkwood Rd

Boise, ID 83709

jaycarlisle@boisestate.edu

Other Observers: Craig Fosdick, Dave Hazelton

Date Report Prepared: 1-8-07

Date Sighting Occurred: 12-23-06, about 915am

Locality of Observation: CJ Strike Dam, border of Elmore & Owyhee Counties

Habitat: reservoir below dam

Conditions: partly cloudy and windy; I used Swarovski EL 10x42 binoculars and a Fujinon 80mm spotting scope (20-60 zoom) at between 20-40x.

Did you take notes? not at all

Did you consult a field guide or other reference work? during the observation

What guide(s) or reference(s) did you consult?

Sibley & National Geographic

Description: The bird was very large (Herring Gull size or larger) in comparison to nearby Ring-billed Gulls; had a large, all-dark bill; was uniformly light brownish-gray; and had wingtips uniform in color with the body.

Behavior: The bird was roosting/loafing with a large group of Ring-billed Gulls on the water below the dam.

How and when did you positively identify the bird, and what clinched the identification for you? ID was clinched by large size; large, dark bill; brownish-gray overall color; and the pale wingtips (similar to mantle).

How did you eliminate similar species, and what were they? Possibilities include Herring (dark wingtips, different head shape), Thayer’s Gull (smaller size, darker wingtips, smaller bill), Glaucous Gull (paler wingtips, limited streaking, and two-toned bill), and hybrids with the similarly-shaped Western Gull. A hybrid Western/Glaucous-winged Gull would be expected to have wingtips darker that the body.

Experience with this species (and similar species): I have observed hundreds of Glaucous-winged Gulls (all ages) along the west coast (especially Washington), including 2 above CJ Strike dam in Dec 2005 and 2 others at CJ Strike between Oct-Dec 2006. I have observed countless Herring, large #s of Thayer’s (especially in winter in Oregon & Washington but many inland sightings from Idaho to South Dakota), and numerous Glaucous Gulls (Alaska, Idaho, South Dakota, etc.). I have also observed a number of Western x Glaucous-winged hybrids on the west coast – including a week ago (a week after seeing this bird – a week prior to preparing this report).

General birding experience: extensive; 14+ years in US and Latin America

Were photo(s), video, and/or audio obtained by you? (If yes, please include or attach) Yes; see the 2 pictures (very poor quality – taken thru my scope) of this bird attached.

[2/21/07 -- Larry Ridenhour also submitted photos to J. Carlisle regarding this bird -- and gave permission for Jay to append those photos to this report -- Bottom 4 photos are from Mr. Ridenhour].

PHOTOS BY Larry Ridenhour, below

END PHOTOS by L. Ridenhour.