 |
Camping & Wilderness |  |
Parks & Conservation |
 |
Wildlife & Biodiversity |
 |
Monitoring the Environment |
 |
Fishing |  |
Hunting & Trapping |
 |
Education & Youth |
 |
Publications, Maps & Data |
Northern Flying Squirrel
THE SPECIES: Glaucomys sabrinus
Clinging to the trunk of a spruce tree twenty metres above the forest floor, a northern flying squirrel turns head down, gathers its muscles, and leaps into space. With four limbs spread wide and the loose skin between them stretched out to create a parachute effect, the squirrel glides for fifty metres, twisting and turning through the trees. Approaching its chosen landing site, it swoops upward at the last moment, checking its speed before settling onto the lower trunk of another large spruce. The squirrel quickly scrambles a few metres up the tree before pausing to survey its new surroundings.
The northern flying squirrel is fairly common in Canada's boreal forests, but because it is a nocturnal species, few people have ever seen one. Most Yukoners are unaware of the flying squirrel's presence in the territory.
DISTRIBUTION
Since the flying squirrel has been little studied in the Yukon, its local distribution is not well known. It is thought to occur from the B.C. border north to Dawson City, but the exact northern limit of its range has not been documented.
This squirrel inhabits dense coniferous forests with large mature trees, and is likely confined to lower elevations in the Yukon.
CHARACTERISTICS
Thanks to its long tail and the mass of skin folded along its flanks, the northern flying squirrel appears to be almost the same size as the red squirrel. But with its delicate body structure, it is considerably lighter. Weights range from 75 to 140 grams, about half the weight of a red squirrel. The northern flying squirrel is larger than the southern flying squirrel which occupies southeastern North America.
Brownish grey fur on the top surface of the flying squirrel's body contrasts sharply with the pale, cream coloured underparts.
The loose skin that extends from wrist to ankle is folded along its flanks when not "in flight." These membranes, which make the flying squirrel less agile on the ground than the red squirrel, function beautifully in the air. Spurs of cartilage extending back from the wrists help to spread the folds of skin. With the aid of its flattened tail, the flying squirrel is able to bank and turn in mid-glide. The large luminous eyes of a nocturnal hunter contribute to the flying squirrel's unique appearance.
LIFE HISTORY
Northern flying squirrels probably mate in late March and April, with females giving birth to an average of three young in May. The young are born in a tree nest from three to thirty feet above the ground. The nest may be a renovated bird nest, a mass of twigs, moss, and shredded bark arranged around the base of a branch, or an abandoned woodpecker hole or other cavity in the tree trunk. Tree trunk nests are thought to be more commonly used in winter.
At forty days old, young flying squirrels are walking well but are unable to glide. Occasionally, a mother will glide while holding one of the young with her mouth. At three months of age, the young begin their gliding lessons, and by September they are as mobile as their parents. Young females will be ready to breed the following spring.
Unlike red squirrels, flying squirrels are very sociable.
Several adults may feed in a group, and nests are often located close together. In Alaska, as many as 20 flying squirrels have been found sleeping in a single communal winter nest.
Northern flying squirrels sleep through the daylight hours and rise to feed after dark. In southern parts of their range, peaks of activity are thought to occur at 11 PM and again at 3:30 AM. Flying squirrels are not active during windy nights, but may be out foraging in late afternoons on cloudy days. It is not known how the long daylight hours of the Yukon summer and the long periods of darkness in winter affect the activity patterns of this nocturnal mammal.
The primary foods of northern flying squirrels are tree lichens, fungi, and the buds, leaves, seeds and fruit of many trees and shrubs. It also eats insects, bird eggs, and fledgling birds, and may scavenge off any carcasses in the area. Much of its foraging is done on the ground. Cones are stored in tree cavities and nests for the winter, and these supplies allow the squirrels to remain near dormant in their nests during blizzards and periods of extreme cold.
Flying squirrels glide from one tree to another to forage, but also to escape predators. Owls are their main predator, but foxes, weasels, marten, and even lynx and wolves occasionally eat flying squirrels.
FLYING SQUIRRELS AND PEOPLE
As noted earlier, most Yukoners are unaware of the flying squirrel's existence. It is occasionally caught in traps set for other furbearers, but its pelt has no market value.
The true value of this unique and mysterious mammal may lie in the wonder and appreciation for nature that it inspires in many people.
VIEWING OPPORTUNITIES
How do you view a small animal that only comes out at night?
Well, usually you don't, but there are exceptions. More than one Whitehorse resident has been fortunate enough to have a flying squirrel land on a bird feeder near a window.
During the longest days of a Yukon summer, the dark hours are short and still fairly well lit. Since the squirrels will be more visible, this may be the best time to look for them in dense, mature spruce forests, or to visit a nest you may have located.
Knocking on the trunk of a tree with a squirrel nest in it may bring a flying squirrel out, but be careful. Continued harassment may cause the squirrels to abandon their nest.
Flying squirrels are less active in winter, but you can still look for the characteristic landing patch with tracks leading off in the snow.