While searching for information on the status of Canada Goose subspecies in North America, I came across the following link that has a good summary of which populations are assigned to what species. You can access it here. As I figured, there is still considerable debate over how many subspecies should be assigned as well as complications over the naming of the smaller-bodied species, Cackling Goose ('Cackling' Goose was formerly considered a subspecies of Canada but now 4 subspecies are listed under the newly split species, Cackling Goose!).
After reading it, I certainly agree with the author on two major points: 1) This has certainly rejuvenated the study of the Canada Goose and Cackling Goose in North America and better data might now be found to bring new information to the status of the many subspecies (which will aid in conservation). 2) There is much study needed at the intermediate level, particularly with parvipes that has been grouped under Canada Goose and taverneri, that has been grouped under Cackling Goose.
The article states that there are also suggestions to split the North American population into 2-4 species! Although I haven't read the research behind these suggestions, this seems a little out of hand at this point if we're already having trouble classifying subspecies into 2 different groups. Don't get me wrong, I agree that we should constantly be studying taxonomy to look for species splits, but in some cases, it seems that 2 species are split that still have broad range overlaps and many intermediate birds that can't be classified. The Canada/Cackling Goose is definitely the perfect example and much more study is needed in my opinion. There are a lot more articles out there on the topic that be found through a simple Google search.
Which brings me to another discovery in the article. David Sibley has his own blog! I'm elated to see that he provides updates online including discussions of identification, conservation, taxonomy, and sightings. His blog, Sibley Guides Notebook is a great read and he currently has a discussion of the Ivory-billed Woodpecker controversy and also a compelling discussion of the status of Great White Heron - species, colour morph, or subspecies? Sibley also has a discussion of the Canada/Cackling Goose on his website that you can reach here. I definitely recommend checking it all out.
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