Furry Friday: Flying Squirrels

Update: For the first time, the group (45 people) did not get to see the Flying Squirrels on March 20, and we didn’t hear any Saw-whet Owls either. It was a very humid, misty, foggy night with the temperature near freezing, so that may have had something to do with it.

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Posted by Bob Lefebvre, all photos by Dan Arndt

Next Friday, March 20, Dan Arndt and I will lead the annual Nature Calgary outing to the Weaselhead to see Northern Flying Squirrels. This is a popular outing, likely because people don’t often get an opportunity to see these animals. It can also be challenging, because we often have to wait for over an hour in the cold and dark before the squirrels make an appearance. But if you are patient there is a very good chance you will see these elusive creatures. In over a dozen trips to see them, I think we have only missed them twice. We generally get to see them glide, and we see them up close at a particular bird feeder which they apparently visit each night, looking for seeds that the birds have overlooked (we re-stock the feeder just before the field trip so that they will stay and feed for a while).

For birders, we often hear Northern Saw-whet Owls and sometimes other species.

If you want to join us, we meet at the north Weaselhead parking lot, 37 Street and 66 Avenue SW, at 8 pm, Friday March 20. Here is the information about the field trip on the Nature Calgary site.

Many people are not even aware that we have flying squirrels in Calgary (I wasn’t until we saw one at this location in 2008), but they are in fact common throughout the boreal forest, and probably in the city as well. Because they are nocturnal they aren’t often seen.

Most of the photos below were taken last spring on one of our scouting trips. We set up in the bush within ten feet of the feeder, and were able to get great looks. All photos by Dan Arndt, March 26, 2014, except as indicated.

Below is a Northern Flying Squirrel approaching the feeder after landing higher in the tree. You can see the wide flattened tail which acts as a rudder and as an additional gliding surface. (This photo taken March 23, 2012, by Dan Arndt.)

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The next shot shows the large eyes and the furred flap of skin with a dark edge between the wrist and ankle. This is called the patagium, and it forms the main gliding surface when the legs are extended. (This photo was taken by Dan Arndt on March 17, 2012.)

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Below, a Northern Flying Squirrel at the feeder:

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Below, Feeding. Note the patagium extending from the forward part of the wrist. There is a cartilaginous rod several centimeters long (inside the patagium) jutting out from the wrist, which helps to support the skin.

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The remaining photos were actually taken before the 2014 flash photos above. We use a red light to locate the squirrels. Apparently they can’t see these wavelengths, so it doesn’t disturb them, and we can see them approach. Once they are feeding they settle in and are more tolerant, and do not usually leave even when you use flash photography or approach them more closely.

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Here is another post that Dan wrote after our 2012 field trip: Barred Owls and Flying Squirrels.

More facts about the Northern Flying Squirrel:

  • occurs throughout the forested regions of Canada, except Vancouver Island and the island of Newfoundland
  • absent from the treeless arctic and great plains
  • the similar Southern Flying Squirrel occupies the eastern US and parts of southern Ontario and Quebec
  • the Southern species is rapidly expanding northwards, and is hybridizing with the Northern
  • since Northern Flying Squirrels are nocturnal and shy, they are often thought to be scarce, but are in fact well distributed and common
  • with a population density of 0.1 to 3.5 squirrels per hectare, they likely have the highest total population of any squirrel species in Canada. This is a minimum of 260 squirrels per square mile in the poorest parts of its range, up to over 900 per square mile in food-rich areas
  • they are active all year, and breed from March to June
  • usually nest in tree cavities (abandoned nests of other squirrels or birds), but may construct a drey in summer
  • are clumsy walkers
  • can glide up to 65 metres, dropping about 1 metre for each 2 metres of glide length
  • are very maneuverable, able to make a 90-degree turn in flight, or even to corkscrew around a tree and land on the same tree at a lower point
  • after landing on a tree, they immediately scurry around to the other side, in case they are being pursued or watched by a predator
  • are preyed upon by owls, hawks, weasels, coyotes, raccoons, bobcats, lynx, wolves, foxes, cougars, and domestic cats
  • are especially vulnerable to large nocturnal owls like Great Horned and Barred Owls
  • in Oregon, Northern Flying Squirrels make up about 50-60% of the diet of the endangered Spotted Owl, which consumes an average of 260 squirrels per owl per year
  • Northern Flying Squirrels eat mainly fungi (especially truffles) and lichen, along with seeds and nuts of trees. They supplement this with fruit, tree sap, buds, insects, small birds and eggs, small mammals, and carrion
  • they are a keystone species, vital to their environment due to their feeding activities which disperse tree seeds and the spores of symbiotic fungi throughout the forest

Join us next Friday for a chance to see these amazing animals!

My main source for information on Northern Flying Squirrels was the excellent book The Natural History of Canadian Mammals by Donna Naughton.

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