ALWAYS IN SEASON: Canada geese: Abundant, tough … and controversial
Pretty hard to miss Canada geese last week. Anyone who went outside must have seen them. Or heard them.
This is an experience not everyone could have expected half a century ago. Geese are far more abundant now than they were in our grandparents’ time, and probably more abundant than they have ever been.
This is true of Canada geese, which have increased over time. This goose is a common nesting species across the plains; in the 1970s, nesting geese were almost unknown here.
Snow geese have become so abundant that they are damaging their nesting habitat. Wildlife managers are trying to reduce their numbers, in part by adding a spring season on the birds.
The goose family is represented locally by two other species.
The white-fronted goose is much less common, but still a regular migrant here. This species is named for a white patch just behind the bill, not for its belly, which is marked with dark stripes. This is noticeable when the bird is in flight; the white face can be seen only at close range, when birds are aground.
The fourth goose species that occurs here is the Ross’ goose. This is a smaller version of the snow goose, with a noticeably shorter bill. Again, though, this is apparent only when the bird is seen at close range.
Ross’ geese are rare here, but occur frequently enough that they’re worth watching for. Ross’ usually occur in flocks of snow geese, and searching a flock of snow geese can easily occupy an hour.
The Canada goose itself is an object of controversy and even contempt in some quarters.
The contempt arises from the bird’s fondness for close-cropped grass, such as occurs in parks and on golf courses. Unfortunately for humans using these areas, geese answer nature’s call wherever they’re standing, and since they are big birds, they make quite a mess.
The scientific world is rife with controversy about Canada geese. This involves how to classify the birds. Are they one species? Several species? How many subspecies might there be?
Current consensus — though this is hardly a unanimous opinion — divides the Canada goose and cackling goose, a smaller version. This is a recent development, occurring after the “splitters” gained pre-eminence among taxonomists.
Distinguishing cackling geese from Canada geese is a challenge, though plenty of people claim to be able to do it. Myself? I’ve left that to the experts who can spin out DNA samples and reach conclusions that elude me.
Some authorities consider the larger birds that nest across the plains to be a separate species, the giant Canada goose. Others regard this as a subspecies.
Giant Canada geese are similar to other Canada geese in every respect — but they are markedly larger, and this is obvious at a glance, especially in a mixed flock.
Current consensus counts six other subspecies, mostly based on breeding ranges.
Consensus now counts several — four or six or more — subspecies of cackling geese.
But this is hardly the end of the controversy. One authority suggested there are six separate species in the Canada/cackling goose complex and as many as 200 subspecies!
What’s a poor birder to do?
Wait it out, I think.
My go-to source, “The Birds of North America,” published with support from the American Ornithological Union, didn’t list the cackling goose as a separate species as recently as 2002. Instead, the authors noted, “The Canada goose exhibits ... perhaps the most extreme intraspecific differences in body size among birds.”
In general, the smaller, lighter birds are now regarded as “cackling” geese, while Canada geese include the larger and darker birds.
Whatever their genetic relationship, these geese are practically indistinguishable in the field or in the air.
Still, geese of any kind are welcome harbingers of spring, and spring’s sudden arrival last week brought thousands of geese through the Red River Valley.
The geese are in a hurry: Nesting season is short enough in the Arctic, and the extraordinary winter has delayed its start.
It’s worth noting that not all geese are migrants here. For at least the last two years, hundreds of geese have taken advantage of open water at the municipal lagoon and survived a North Dakota winter.
That’s pretty good evidence of the adaptability and toughness of the goose family.
Jacobs is a former publisher of the Herald. Reach him at firstname.lastname@example.org.