Split of Canada\Cackling Goose
With the recently published 45th supplement to the Check-list of North American Birds the American Ornithologist's Union's Committee on Classification and Nomenclature (Banks et al. 2004) split the Canada Goose (Branta canadensis) into two species: Canada Goose (B. canadensis) and Cackling Goose (Branta hutchinsii). The larger subspecies are included under B. canadensis with the smaller subspecies included under B. hutchinsii.
In Texas, both of these species occur in the state and are relatively common in some areas. With this change in taxonomy there will, of course, be greater scrutiny on these birds and there is much to be learned about the distribution and relative abundance of Cackling Goose in particular. There are several subspecies of B. canadensis known (or believed) to occur within the state. Here is a breakdown of Cackling Goose and Canada Goose subspecies:
Canada Goose - B. c. moffitti - This is another large subspecies that is lighter in overall body plumage than B. c. interior. Moffitt's is also thought to be an uncommon migrant in central and eastern Texas and an uncommon winter resident along the coast. Grieb (1970) stated that this subspecies constituted a small percentage of the birds wintering in the Panhandle, however that wintering population has undergone tremendous growth in the past three decades and the current makeup of the population may be different.
Canada Goose - B. c. parvipes - This subspecies is also known as the Lesser Canada Goose and is medium sized and proportioned. Grieb (1970) stated that 90-95 percent of the birds wintering in the Panhandle consisted of this subspecies. They are also thought to be rare migrants elsewhere in Texas and rare in winter on the coastal prairies. This subspecies is intermediate in size between the larger subspecies listed above and the Cackling Goose.
Cackling Goose B. h. hutchinsii - This species is a common migrant in central and eastern Texas and a common to uncommon winter resident along the coastal plain and in the Panhandle and South Plains. This small goose is pale in overall body plumage.
Other Canada Goose subspecies have been reported as follows:
B. c. interior - This is a large subspecies that is thought to be an uncommon migrant and winter resident in eastern half of the state and along the coastal plain.
B. h. minima Ridgway
There is one documented record of this subspecies (a specimen from Kleberg County) and a couple of other sight records that are thought to pertain to this subspecies. B. h. minima are much darker in overall body plumage than B. h. hutchinsii.
There are likely to be identification problems with some "Canada" Geese seen in Texas simply because all three "sizes" of birds occur in numbers in the state. Large individuals of the largest subspecies of Canada Goose (B. c. interior and B. c. moffitti) should be readily identifiable, as should the smaller Cackling Geese. However, "Lesser Canada" Geese (B. c. parvipes) appear to overlap significantly with both the larger Canada subspecies and Cackling Goose. Certainly more information about these birds will be forthcoming and this identification dilemma will be lessened in the next few years, but for now, caution is advised when looking at intermediate sized Canada-type geese. Furthermore, the Check-list Committee suggested that further taxonomic revisions maybe forthcoming. This would suggest that careful examination of Canada-type geese in an attempt to identify subspecies (or subspecies groups) may be of further value in the not-too-distant future.
The Texas Cooperative Wildlife Collection at Texas A&M University contains these specimens: B. h. hutchinsii from Waller and Wharton Counties; B. h. taverneri from Irion and Waller Counties; B. c. parvipes from Waller County. These were confiscated in 1969 from a hunter in Waller County and were identified by John Aldrich, then of the USFWS and the U.S. National Museum.
Other Cackling Goose subspecies have been reported as follows:
B. h. taverneri
This is a medium-sized subspecies. There are specimens from Irion and Waller Counties and the subspecies is generally thought to be a rare to very rare migrant and winter visitor to Texas. Considering the range of the subspecies (breeding in western Alaska and wintering on the Pacific Coast), they are likely a very rare visitor at best. How this subspecies can be separated from B. h. hutchinsii is unknown to me at this time.
Banks, R. C., C. Cicero, J. L. Dunn, A. W. Kratter, P. C. Rasmussen, J. V. Remsen, J. D. Rising, D. F. Stotz. 2004. Forty-fifth supplement to the American Ornithologists' Union Check-list of North American Birds. Auk 121:985-995.
Grieb, J. R. 1970. The shortgrass Canada goose population. The Wildlife Soc. Monogr. 22. Washington, D. C.
Secretary, Texas Bird Records Committee, February 2005