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Feature Article - November 10, 2005

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Feature Article

November 10, 2005

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ArchiveImage GalleryAlgonquin Land Claims

Gray MerriamLegaleseGeneral information and opinion on legal topics by Rural Legal ServicesNature Reflectionsby Jean GriffinNight Skiesby Leo Enright

Did you know that Flying Squirrels are forest canaries?

commentary by Gray Merriam

Ever hear the gentle thumps of a squadron of flying squirrels landing on the siding of your house? I have. Around here we have a lot of Southern Flying Squirrels, known to biologists as Glaucomys volans. They probably are several-fold more numerous than the daytime red squirrels. We also are in the range of overlap with the larger Northern Flying Squirrels, Glaucomys sabrinus that are more common in purely coniferous forests.

You can get to see and hear our flying squirrels by offering a nighttime feast of sunflower seeds or nuts in your bird feeder or even in a container on the ground near a tree or a house wall. They are not fearful of a beam of light or even a small porch light.


In the daytime, flying squirrels hole up in hollow trees or sometimes build a twig nest in the high branches. By night they forage for many things. Nuts, such as this year’s bumper crop of acorns are a favourite. So are moths and other large insects, mice and voles, and even eggs and nestling birds in season. But a more common food is mushrooms – fungi – either above ground or underground.

Most of a mushroom is underground. The aboveground part appears only periodically as a means of producing spores to reproduce and spread the mushrooms. Underground, there is much more of many fungi. Often there are many square miles of root-like filaments called hyphal strands making fungi the largest living beings. Many of those hyphal strands are attached intimately to the tissues of tree roots. The trees use those fungal strands as extensions to their own root system. A marvelous increase in the tree’s ability to absorb scarce nutrients. It is a symbiosis. In return the fungus gets some nutrients made by the tree using sunlight – something the fungus can’t do. But it seems that the tree gets the best deal because without those hyphal strands on their roots – called mycorrhyzal strands – many tree species do not survive well. Some fungi produce fleshy bodies underground – the delicacy called truffles. Flying squirrels are expert truffle sniffers and enjoy these underground fungal delicacies as much as any French gourmet might.

Trees need those mycorrhyzal fungi and the flying squirrels ensure a constant crop. The flying squirrels eat both above-ground and under-ground parts of the fungi, including the spores that produce new fungi. And many of those spores pass through the flying squirrels. Those spores are compacted into pellets that also contain a concentrate of nutrients. So the flying squirrels drop concentrated forest pellets of forest health supplement right at the base of the trees that need it. Without the flying squirrels the forest trees are less healthy.

Many other animals that live in the forest also are supported by flying squirrels. They are a major food source for many predators, especially owls. In old-growth forest in BC and in the Pacific Northwest of the US, a pair of Northern Spotted Owl have been found to eat over 400 northern flying squirrels in a year. Northern Spotted Owls are considered to be the prime indicator of healthy old-growth forest.

So because of their role in maintaining healthy symbiotic fungal populations in the forest and because they are a major food supply for many forest predators, northern flying squirrels are now being thought of as a prime indicator of a healthy forest. Canaries in the forest. Just like canaries in the mines.

But beyond that utility value, seeing a flying squirrel climb a tree, launch into an eighty foot glide to a lower landing on another tree, climb up and repeat the feat, is a wonderful sight – whether you see it or just imagine it.

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