Cackling Goose -- Canada Goose Subspecies Identification Indicators
by Harry Krueger
|Cackling Goose, B. h.
Photo © 2004 Gabor Papp
October 2004, Ann Morrison Memorial Park, Boise, Idaho
Small geese are always Cackling Goose and larger geese are always Canada Goose, right? Wrong. If relying on size alone as the differentiating factor in identifying these two possibilities, misidentifications are sure to be made. Fortunately geese are social creatures and comparison to others is sometimes useful, although far from definitive because of the overlap between subspecies and now even species (size ranges from a large 15-20 lbs. in maxima to Mallard size birds of about 3 lbs. in some minima). Making such a tricky id based on any lone bird is more than risky. Understand that field identification of these two species is based on previous work done on the recognized eleven subspecies of the former Canada Goose, none of which is very complete, often resulting in pointed disagreements among "experts."
Because of intergrades, human assisted transplants, changing environmental factors, and a still developing understanding of each of these races and their interactions with each other, it will often be impossible for even the most skilled and well informed field observer to identify each goose they encounter. In fact, many may just be comfortably, and most reasonably, lumped into a catch-all category of "White-cheeked Goose." Hopefully this article will at least lessen the number of generic "white-cheeked" geese tallied in the field and prevent some level of confusion and/or misidentification.
Formerly there were 11 recognized subspecies of Canada Goose (Sibley pictures 6, National Geographic pictures 5). Cackling Goose includes the subspecies hutchinsii, asiatica (probably extinct), leucopareia, taverneri, and minima. If you're looking at Sibley this includes his Aleutian, Cackling, Richardson's, and Lesser (this subspecies was split between the two species, with part to Cackling). Canada Goose now includes the subspecies canadensis, interior, maxima, moffitti, parvipes, fulva, and occidentalis. In Sibley's that's Dusky, Common, Lesser (subspecies split, with part to Canada) and the nominate Canada (or "Atlantic" in NGS). Making things more interesting for field identification is the fact that there is a complete overlap in size between the two new species, with taverneri (Cackling) and parvipes (Canada), both divisions of "Lesser," almost equal in size.
Note: Identifying Cackling and Canada Goose by size alone, which many are prone to do, is a risky proposition for all races but the very small Cackling Goose, Branta hutchinsii minima. This is not what we have chosen to call a "primary indicator," or a field mark or characteristic that gives the observer a unique indication of the identification of a specific species or subspecies. For example throughout the "white-cheeked" goose complex we believe that bill and head size and shape relationship is generally a primary indicator, whereas size and/or plumage is usually a secondary indicator, or field mark or characteristic, while perhaps very helpful in discerning the identity of a species or subspecies in association with a primary indicator, often does not by itself provide the surety of id desired by most observers. The terms primary indicator and secondary indicator are used throughout this article.
Following is a summary of secondary size and plumage indicators for the various subspecies of Canada and Cackling Goose (Stackhouse 2004) that may be helpful in beginning to get a firmer grip on this emerging id challenge. See the "Detailed Guide to 'White-cheeked' Geese Subspecies" (work in progress) for more specific particulars.
Canada Goose (Branta canadensis)
Cackling Goose (Branta hutchinsii)
Icon photo credits: canadensis: Angus Wilson; interior: David Roemer;moffitti: Harry Krueger; parvipes: Stuart MacKay; hutchinsii: Harry Krueger; minima: Gabor Papp
WHITE-CHEEKED GOOSE: [Introduction] [Subspecies Accounts] [Descriptive Comparisons] [Additional Photos] [References]
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