Formerly considered a "Bird of Mystery," the identification and status of the Tule Goose appears to have been settled. Here is a comparison of an adult "Tule Goose" (A. a. elgasi) standing with a typical west coast Greater White-fronted Goose ("A. a. sponsa" - sometimes synonymized with "A. a. frontalis") resting below. Note the Tule's larger size, bigger darker head, longer bill, longer neck, more extensive white forehand, and reduced white side stripe. Another helpful feature is Tule's reduced dark belly barring which can be seen here and the pale belly contrasts more with the dark body on Tule Goose.
Tule Goose is currently treated as a large, dark race of the Greater White-fronted Goose but is a candidate for splitting (AOS 35th supplement). They breed only at the north end of Cook Inlet in Alaska where their population numbers about 7,500. They winter primarily at scattered locations in the Northern Sacramento Valley where they occur along with the smaller more widespread subspecies "A. a. sponsa."
The Tule Goose was not properly described to science until 1975. The name "A. a. gambeli" applied to this taxon by some authors is wrong and based on specimens collected in Texas, a different subspecies.
Those who have the outstanding "Waterfowl of North America Europe & Asia" by Sebastien Reeber (2015), I question two of the images (61 & 63) labeled "elgasi" on page 218. I would call them "sponsa."
