Thursday, November 14, 2013

Lesser Canada Goose?


I spotted this fellow resting at the edge of Cranberry Lake in Deception Pass State Park.  There was something about his beak that caught my eye.  It looked smaller than I would expect for a Canada Goose (Branta canadensis).  I wondered if I had spotted a Cackling Goose instead.

When I got home and started studying the question, I found myself mired in a very complicated subject.  My Sibley lists six subspecies of Canada Goose, Aleutian, Cackling, Dusky, Richardson's, Lesser and Common.  National Geographic refers to "approximately seven named subspecies."  The phrase "approximately seven" would indicate a hesitancy to commit.  It also lists the Cackling Goose as a separate species, Branta hutchinsii.

Seattle Audubon indicates there are five subspecies that occur in Washington, Western, Lesser, Dusky, Vancouver and more rarely Giant.  It also lists the Cackling Goose as a separate species.

Finally, Wikipedia lists seven subspecies, Dusky, Vancouver, Lesser, Moffitt's, Giant, Interior and Atlantic.  Then, of course, there can be hybrids among these subspecies.  I believe Wikipedia sums it up best when speaking of "confusion and debate among ornithologists."


So, returning to my friend at Cranberry Lake, I have decided this might be a Lesser Canada Goose, Branta canadensis parvipes.  His beak looks too small to be a Common Canada Goose and too large to be a Cackling Goose.  This fellow is also not as big as other Canada Geese I have seen, another characteristic that would point to the "Lesser" subspecies.  But like National Geographic, I am not ready to commit to that.  I would be interested to hear from anyone who might know more than I do about identifying these birds.

Another unusual feature about this guy was that he was alone.  Canada Geese are gregarious birds, almost always seen in groups.  I have read that if one is injured during migration, a companion or mate will stay behind until the bird either recovers or dies.  This is a characteristic I admire.

Frankly, I sometimes wonder if we may be overthinking the subject of subspecies among birds.  Consider the huge genetic variation within the domestic dog, Canis lupus familiaris.  In ten thousand years, if scientists found the bones of Shaquille O'Neal, Peter Dinklage and me, would they consider us three different species or subspecies of human?  Is it possible, as in my Homo sapiens example, we are just seeing normal genetic variations of Branta canadensis?



Meanwhile, the fall migration continues back home along my beach on South Fidalgo Island.  Can you understand from these photos why the Canada Goose is one of my favorite birds?

1 comment:

Laura Mae said...

Great analogy - about scientists finding the bones of three humans in 10,000 years! I too have noticed and wondered why ornithologists have not put their foot down and agreed on the number/names of Canada Goose species. Seems so unusual as compared to other species. Canada Geese are among my favorites. Tolerant, peaceful and loyal. Humans could take a few cues from geese…!

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