After spending two winters in a row in the deep freeze, it looks like this one is going be one of those depressing, gray ones. It also makes it easier for me to imagine the real effects of climate change, even though the global climate was definitely changing when we were having -20 degree nights last year.
One of the real effects of climate change is that the ranges of animals are changing. Those native to cold climates are pushed deeper into arctic and subarctic climates, while those from more southerly climes work their way north.
Nine-banded armadillos are being spotted in Virginia for the first time ever. The Virginia opossum continues its conquest of North America, and the gray fox is starting make its presence known in Canada beyond its typical range of Southern Ontario and Southwestern Quebec.
The gray fox is very common in the United States. If you live east of the Great Plains and near some woods, you’re likely not far from a gray fox. We take the animal almost for granted.
The gray fox does range into Canada, but it’s generally found only near the US border. As far as I know, the only breeding population that has ever existed in Canada is in Southern Ontario into Southwestern Quebec, and currently, the only listed breeding population is on Pelee Island, which is between Detroit and Cleveland on Lake Erie.
Climate change means that winters are getting milder, on average, and this means that Eastern Canada is likely to experience an upward growth of gray fox populations as time goes on. I think this a fair trade. The red foxes we have in the Eastern US migrated from Eastern Canada as the forests were cleared, and as the climate warms, our gray fox will become part of its native fauna.
In 2008, the potential of the gray fox becoming more established in Canada was realized when a gray fox was caught in a beaver trap in Charlotte County, New Brunswick. This gray fox was well north of its breeding range. The nearest breeding population is just east of Bangor, Maine, so this fox was a long way from home. The fox had traveled something like 84 miles, which is pretty long distance for an animal that is usually a bit smaller than a pug. The young dog foxes of this species do occasionally make wide dispersals from their parents’ territories, and this one made a big run from his mother’s den. He was a subadult, just lighting out for the territories.
The stomach revealed the last meal of the fox– a ruffed grouse. Parasites in his small intestine revealed that he’d been living on snowshoe hares, probably his entire short life.
The authors who explored the New Brunswick gray fox case examined the historical distribution of the species. We have archaeological records of gray foxes from Manitoba, Ontario, and at least Cumberland County Maine, but 350 years ago, the population crashed in Canada. It also crashed in the Great Lakes region of the US, northern New York, and Northern New England. Then in the period from 1930 to 1940, it began to recolonize much of northern New England and the Great Lakes states. They do occasionally wander into Quebec, Ontario, and extreme southern Manitoba.
But with a warming climate, it looks like the gray fox is moving north, and it is very likely that breeding populations will be found deeper into Canada.
No one had ever heard of a gray fox in New Brunswick, but it may not be long before they really do become established well outside of their historic range.
I once read that the main thing keeping them from spreading north was they were too reliant upon cottontail rabbits as a prey source, but apparently their numbers have only increased in Maine as the rabbit population has crashed. Maine, like most of northern New England, is becoming more and more forested, and those forests are maturing. Cottontail rabbits don’t like that particular habitat, and what’s more, Eastern cottontails aren’t actually native to Maine. They were introduced for sporting purposes, and they thrived in the land of small farms.
Gray foxes prefer forested habitat, and they have spread well outside the range of cottontail rabbits in Maine. The remains of the dear New Brunswick fox revealed that the gray foxes of Maine were living well on snowshoe hares and ruffed grouse. They simply don’t need cottontails to thrive.
If gray foxes do become more established in Canada, it will be interesting to see what kind of foxes actually do evolve to adapt to that part of the world. Will they be bigger (in keeping with Bergmann’s rule)? Will they grow thicker coats?
Only time will tell.