IBRC 18-B-10

IDAHO BIRD RECORDS COMMITTEE
RARE BIRD REPORT FORM

SPECIES: Cackling Goose (Branta hutchinsii)
HOW MANY: 1 - “Aleutian” (B.h. leucopareia)

REPORTER: Doug Ward 8362 Selkirk Ct. Hayden, ID 83835
REPORTER EMAIL: ward@revettminerals.com
OTHER OBSERVERS: None.

DATE REPORT PREPARED: 2/3/2010
DATE SIGHTING OCCURRED: 24 January 2010

LOCALITY OF OBSERVATION: Cougar Bay (BLM Access), Lake Coeur d’Alene; Kootenai County, Idaho
HABITAT: Ice covered and open water bay; mudflat beach.
CONDITIONS: Bird was seen about 100m from observation point on the beach. Observed between 3:30 – 4:15pm using both 8X40 binoculars and a 15-40X spotting scope (15-25X during observation). Lighting was cloudy, bright overcast with sun at my back.

DID YOU TAKE NOTES?: Yes, later the same day
DID YOU CONSULT FIELD GUIDE OR OTHER REFERENCES?: Yes, another day after the observation
WHAT GUIDE(S) OR REFERENCE(S) DID YOU CONSULT?:
1)“Distribution and Identification of Cackling Goose (Branta hutchinsii) Subspecies”; Mlodinow etal; North American Birds (pp 344-360 Vol.62; 2008)
2)“Complete Birds of North America”; National Geographic; 2005

DESCRIPTION: “Aleutian” (B.h. leucopareia) – small, uniformly colored dark brown goose with black head and neck, white cheek patch and broad white half collar at base of neck. Description in comparison to “Taverner’s” (B.h. taverneri) Cackling Geese (see separate report)with which it was directly associating. Size & Structure: Similar size and structure to "Taverner's" though head was rounder, and bill slightly shorter. Plumage: Body coloration was generally darker, including dark chest. Broad, bright white half collar separated neck and chest. Cheek/throat patch broad at throat and wrapped behind and above eye.
BEHAVIOR: The “Aleutian” Cackling Goose (B.h. leucopareia) was hanging out with two “Taverner’s” Cackling Geese (B.h. taverneri; see separate report)which were part of a large, loose grouping of Canada Geese (~750 total; ~500 “Greater” ssp. & ~250 “Lesser” ssp.). The Cackling Geese generally stayed associated with each other in groups of 2-5 scattered in the central portion of the larger flock.

HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU? The "Aleutian" (B.h. leucopareia) was immediately noticable as different from all of the geese present by its uniform dark coloration, and bright white half collar.
HOW DID YOU ELIMINATE SIMILAR SPECIES, AND WHAT WERE THEY?
As this was a black necked, white cheeked goose without additional white on the face, only Canada Goose (Branta canadensis) was considered to be addressed at the species level. Additional discussion follows at the subspecific level.

“Greater” Canada Goose (B. canadensis ssp.) is eliminated by the size differential of this bird considered in direct comparison; this bird was ½ the size of the “Greaters” present.

“Lesser” Canada Geese, including the similarly plumaged "Dusky" Canada Goose (B.canadensis ssp.), was also considered for comparison. Fortunately there were numerous “Lessers” available for direct comparison not only in size, but more importantly head and bill structure. This bird was shorter legged, with a shorter, thicker neck, a short (<¾ head length), thick based bill which had a straight culman giving a triangular profile when viewed from the side. It also had a high angled forehead which accentuated the "stubby" billed look. As the two subspecies of “Dusky” Canada Goose are apparently structurally similar to, though larger than the “Lessers” which were present that day, the comments made above distinguishing the “Aleutian” from the “Lessers” apply here as well. Subspecies Discussion: Notes above made before consulting reference material. Subspecific identification based largely on a recent article in North American Birds (see References) as well as a review of photographs from various sources on the internet.

The “Aleutian” Cackling Goose (B.h. leucopareia) present turned out to be the most unusual based on their typical wintering range on the west coast and central Valley of California. The following points are made to justify the identification:

1)Plumage: This bird was in close association with two “Taverner’s” Cackling Geese (B.h. taverneri; see separate report) and was noticeably much darker brown, and much more uniform in coloration. The chest was as dark brown as the sides and back; no noticeable variation in shade. However, the most notable field mark was the broad, bright white half collar which separated the front of the black neck from the brown chest.
2)Similar Subspecies: While the white half collar is certainly a key mark for an “Aleutian”, all of the other subspecies of Cackling Goose can apparently show this feature. However, I think the combination of general coloration (uniform dark brown including chest – effectively eliminating “Taverner’s” & “Richardson’s” (B.h. hutchinsii)), size (similar to “Taverner’s” which eliminates “Ridgway’s” (B.h. minima)), and the white collar substantiate the identification as “Aleutian” Cackling Goose.

EXPERIENCE WITH THIS SPECIES (AND SIMILAR SPECIES): I have not seen this particular subspecies of Cackling Goose (Branta hutchinsii) previously. I'm familiar with "Richardson's" Cackling Goose (B.h. hutchinsii), pre-split, from Colorado and New Mexico where they are regular, and have seen "Ridgway's" (aka "Cackling") Cackling Goose (B.h. minima), also pre-split, a couple of times.
GENERAL BIRDING EXPERIENCE: I've been birding for 37 years and consider myself an "advanced" birder.

WERE PHOTO(S), VIDEO, AND/OR AUDIO OBTAINED BY YOU?: None

NOTE: The label on the lower sketch, the one that says "19 seen", should read B. h. taverneri, not B. h. hutchinsii.

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