The story of the northern flying squirrel

Posted: Friday, December 15, 2000

Few creatures of our forest are more in-your-face than the familiar, brassy red squirrel.

By contrast, its nocturnal cousin, the northern flying squirrel is a shadowy creature of the night that seldom makes its presence known.

If most of us saw a flying squirrel sitting on a branch, we might not recognize it for what it is. But the differences between them are, well, day and night.

Red squirrels and northern flying squirrels are of about the same outer dimensions, but the flying squirrel weighs only half as much, about one-quarter of a pound or the weight of a stick of butter. Its tail is silkier and fluffier, an aide to its airborne movement. Fur of the flying squirrel is grayer, with upper parts ranging from cinnamon to pecan. The eyes are larger and shine a distinctive reddish-orange. They are capable of gathering in every available ray of light for extraordinary night vision.

A biologist would quickly notice the distinctive patagia, a fur-covered fold of skin stretching between the front legs and body. Flying squirrels do not actually fly; they glide. But wildlife biologist Jeff Nichols has observed some pretty incredible maneuverability by these original paragliders. The Juneau U.S. Forest Service employee has watched them glide down, take a 90 degree bank and end up higher on the mountain than they started out. Twenty to 30 yard glides are common and research literature notes downslope glides of about 100 yards.

Although it's fairly certain northern flying squirrels play a pivotal role in the health of the forest, much about their behavior in Alaska is yet unknown.

U.S. Forest Service research wildlife biologist Winston Smith, assisted by Nichols, undertook field studies that commenced in February of 1998. The initial phase of their research was completed just last month.

Their study was conducted on north-central Prince of Wales Island, generally near Honker Divide and Control Lake. The area was selected because it's home to a unique sub-species of flying squirrel in Southeast Alaska, the Prince of Wales Flying Squirrel, and because the island has had more habitat modification due to timber harvest.

There is genetic evidence Prince of Wales northern flying squirrels have been isolated long enough to develop into their own sub-species. The fact that red squirrels do not exist on Prince of Wales made their research easier, though it was not a reason for choosing the site, Smith says.

The flying squirrels were trapped with live traps over a 30-acre grid and marked with ear tags. By continuous trapping in the same area over spring and fall for three years they will be able to estimate abundance, distance of travel, longevity, male-female ratios and age distributions, factors which help paint a more complete picture for management considerations.

The study area included blocks of old growth spruce/hemlock forest, thought to be the primary habitat of flying squirrels. But Nichols and Smith also studied them in an area of mixed conifer scrub forest and muskeg where they found a smaller number of flying squirrels as well. It is promising that flying squirrels use and possibly sustain themselves in areas other than old growth spruce/hemlock forest, Smith says.

The northern flying squirrels' mysterious ways extend to their favored food, truffles growing beneath the surface of the earth. In western Washington and Oregon, truffles make up their primary diet, another distinct difference from the daylight, seed-eating red squirrel. But in Alaska, where flying squirrels also eat lichens, it is not certain to what extent truffles make up their diet.

The forest and flying squirrels are closely interrelated. Flying squirrels eat truffles and distribute spores in their droppings. Spores become mycorrhizae fungi that help tree roots absorb nutrients and develop properly. Thus the forest feeds the flying squirrel and the flying squirrel feeds the forest.

Six to seven species of truffles have been documented in Southeast Alaska just by looking at fecal pellets of squirrels.

Work with flying squirrel offers insights into forest management, Smith says. While they don't yet fully know the importance of the species here, their life history is linked to many characteristics of old growth forest, where truffles do best amid rich decaying matter.

Another unknown is their daily routine. Flying squirrels are mostly nocturnal, but what's a hungry squirrel to do in summer's non-stop daylight? They are found as far north as Fairbanks, when there is virtually no night in summer. There are risks to foraging in daylight for food, including ending up in a predator's diet.

In Southeast it's not known to what extent flying squirrels forage when it's not dark, but Smith and Nichols have never seen a flying squirrel out in daylight hours during their spring and fall field work.

They've set live traps in Juneau, with only limited success. But people have seen flying squirrels at Mile 18-20 Veterans Highway and some have been caught at Lena Point. Other good places to look are near Peterson and Cowee Creeks, Tee Harbor Creek and Fish Creek on Douglas Island.

To see northern flying squirrels yourself, try attracting them with balls made of peanut butter and corn meal. The oily smell may draw them in. But put bait out after dark, or red squirrels will foil your plans by carrying it off first. Then screw a red light into your porch light socket. The squirrel can't see the red light and will think it is dark, but you can see the squirrel. This works best if your house is close to a large patch of trees, including some older trees 100-150 years old.

Smith is now working on an expanded effort to build on information about the northern flying squirrel as it is learned. When you study animals they lead you to further questions, Smith says. And sometimes those questions are more interesting than the ones you originally thought of.

Meet by 8 a.m. Saturday at McDonald's Restaurant downtown or in the valley to participate in the annual Juneau Audubon Christmas Bird Count. For further information call Mark at 789-9841.

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