Rare Bird Report 26-B-08

Idaho Bird Records Committee Rarities Report Form

Species: Black Scoter, female type plumage

Reporter: Cliff Weisse, 4125 Beaver Springs Rd., Island Park, ID 83429, 208-558-7789, cliffandlisa@octobersetters.com

Other Observers: Darren Clark, clarkd@byui.edu; Steve Butterworth; tntbutters@cableone.net; Kit Struthers, kit619@ida.net; Marv Lambrecht, IdLambrech@aol.com, Chuck Trost, trostchuck@cableone.net; Harry Krueger, jhkrueger@gmail.com

Date of Observation: November 7&8, 2008

Date Report Prepared: November 9, 2008

Locality of Observation: Near American Falls Dam on the Snake River, Power County. Directly out from the Cemetery where there is a large gravel/rock island.

Habitat: River

Conditions: Bird was observed at approximate distance about 150 yards. Sun was behind observers and to the side, but birds were in very good light. Observers were above the river at an overlook, especially at the Cemetery. Optics used were Nikon 10 x 42 binocs and Swarovski spotting scope at up to 60x. Bird was observed multiple times of day.

Did you take notes…

during the observation? No

Did you consult a field guide or other reference work?

not at all? No

Description: This description was prepared from notes taken during the observation. Notes were taken while observing one individual and the second bird was similar enough that separate notes were not prepared.

Female type individual. Large diving duck. Not seen in close proximity to other species for direct size comparison, but appeared similar in size to three Surf Scoters present. Overall dark brown. Head dark brown with contrasting pale face, similar in pattern to male Ruddy Duck, with no noticeable difference in color over the light area. Bill blackish and smaller and narrower than bill of Surf Scoters with more concave culmen. Tail was usually held level with the water and I never saw it hold the tail cocked upward. No white was seen in wings at any time, even on actively diving bird viewed from above.

Behavior: Foraging in fairly shallow water by diving repeatedly.

How and when did you positively identify the bird, and what clinched the identification for you? The bird had already been reported by Trost and Krueger. I recognized it immediately when I saw it because of the distinctive face pattern and large size.

How did you eliminate similar species, and what were they?
Ruddy duck is much smaller with bill angled downward and tail cocked upward (a posture that this bird never displayed).

Surf Scoter has large bill with flat culmen and shows variable whitish patches on the face. Some individuals, including one seen close to thie above described bird, show paler face with obviously darker crown/nape but not as pale as Black Scoter and showing two brighter patches in the light area so overall impression is of a dark face with pale whitish spots.

White-winged Scoter has dark head with pale spots on face similar to Surf but without pale face background sometimes shown by Surf Scoter. White secondaries are usually obvious if observed for any length of time.

Other species of diving duck are more patterned than this individual.

Experience with this species: Limited to two previous sightings in Idaho, and a few on a trip to CA 8 years ago, and large flocks on limited visits to NJ in winter where Surf and Black Scoters are usually present in good numbers. I see the occasional Surf and/or White-winged Scoter almost annually.

General experience birding: 14 years

Were photo(s), video, and/or audio obtained by you? No.