Thanks for the help with field identification of Canada Goose
subspecies.

Several people suggested that the geese we saw might be Cackling.
Others, one of whom also observed the birds, thought they were more
likely Taverner's.

I now believe the birds were Taverner's. In my description, I failed
to note that the smaller geese were essentially in proportion with the
larger, rather than having smaller stubby bills and shorter necks,
which would have indicated Cackling.

Here is a summary of what I learned:

The most important characteristics to note are:

1. Relative size
2. Bill size/shape, and head shape/proportions
3. Presence and size of white neck ring
4. Breast color
5. Whether or not the white cheek patches are continuous under the
chin or interrupted by dark feathers
6. Presence of any neck collar or leg band is very useful

The most common subspecies in our area is the Western (Great Basin)
(Branta canadensis moffitti) which breed and winter here.
- Largest CAGO in the West, twice the size of Aleutian
- Relatively slow wingbeat
- Call is a deep, resounding, 'ahh-onk'
- Light breast color
- Long bill and neck
- Could have red (orangish) plastic neck collar

Cackling (B. c. minima) pass through our area on their way to and from
their wintering area in California's Central Valley.
- Smallest CAGO, 1.5 times the size of a Mallard
- Relatively rapid wing beat
- Call is a high-pitched yelp
- Breast dark brown or bronze color, often with purplish cast
- Short, stubby bill, usually less than 1.25 inches long
- White neck ring sometimes present, but generally very thin and
incomplete
- Forehead slopes back from bill, roundish head shape
- Cheek patches often continuous under head, but many separated by
black feathering
- Could have yellow plastic neck collar

The Dusky (B. c. occidentalis) pass through SW Washington on their way
to their main wintering area in the Willamette Valley.
- Medium-sized goose, larger than Lesser, smaller than Western
- Dark breast color, typically a rich chocolaty brown, but may also
tend towards gray
- Neck seems to merge with chest, few birds show neck ring
- localized distribution in California, in northern coastal area

Vancouver (B. c. fulva), which some lump with Dusky, apparently winter
mostly north of Washington, though a few migrate to the Willamette
Valley.

Most of the Taverner's (B. c. taverneri) cross the Cascades to the
Columbia Basin, but some follow path of the Duskys.
- Closely resembles Aleutian in many respects, but usually slightly
larger
- Breast color variable, but usually slightly lighter than Aleutian.
Darker breast than Lesser
- Can have white neck ring on occasion, but almost always incomplete.
- Rounder head than Aleutian
- Usually has continuous white cheek patch under head, but not always

Lesser (B. c. parvipes), which some lump with Taverner's, migrate
mainly (?) east of Washington, to their main wintering area in SE
Colorado.
- Medium-sized goose, usually slightly larger than Taverner's
- Light breast color
- Overall shape and color resembles 'mini-Western'
- White cheek patch almost always continuous under head

Aleutian (B. c. leucopareia) have been confirmed in Washington, though
they are rare. They mostly make landfall in northern California on
their way to the Central Valley.
- Slightly larger than Cackler
- Breast color variable, usually gray-brown, never with purplish cast
- Bill length usually 1.25-1.5 inches
- White neck ring present in *all adults*, usually wide and
pronounced (hatch-year birds generally don't exhibit good neck
ring until first spring)
- Thin dark border of feathering usually present just below white
neck ring
- More abrupt forehead and flatter top to head than other small CAGOs
- Cheek patches nearly always separated by black feathering under
chin
- Could have a light gray plastic neck collar or a colored leg band
(usually blue, yellow, red, or green).

Thanks to Michael Smith who provided field characteristics above.

Thanks also to:

Jon Anderson
Janet Hardin
Jennifer Seavey
Gene Hunn
Steven Feldstein
Harry Nehls

Other references:

Bellrose, F. C. 1976. Ducks, Geese & Swans of North America. 3rd ed.
Johnsgard, P. 1978. Ducks, Geese, and Swans of the World.

Randy Deardorff
curlew at eskimo.com
Seattle, Washington USA