I had heard long ago that there were two groups of Canada geese or two species. I hadn't paid much attention to this before. I knew that there were smaller Canada geese. It's not easy to tell the difference.
Cackling geese are about 25 in long and have a wing span of about 45 in. Average weight is about 3.5 lb. Canada geese are about 45 in. long , wing span 60 in and weigh about 9.8 lb. As you can see there's a big difference in size. However, it's not easy to see this in the field. Cackling geese have a much shorter neck.
There are other slight differences in markings and a big difference in sound.
I was out Nov.5 with a group of birders to Gaetz Lake. There were geese and so we had a good look. They were all the small cackling geese.
Take a look at these birds. Have you seen these differences before?
Populations of geese with the distinctive white "chin-strap" are notoriously hard to classify, largely due to their similar appearance and their ability to roam all over the continent.
ReplyDeleteAfter 2004 the American Ornithologists Union divided the 200 or so populations (races, subspecies, tribes, etc.) between the Canada goose, "Branta canadensis", and the Cackling goose, "Branta hutchinsii". ("B. hutchinsii" is named after Thomas Hutchins, the Hudsons Bay Company surgeon who was the first to document it in the 1700's.)
Further research may lead to more changes in classification. One researcher believes there should be SIX species of chin-strapped geese. Stay tuned.
https://en.wikipedia.org/wiki/Cackling_goose
Geese are not the only birds to be divided and than put back together again.
ReplyDelete