Flying squirrel adventures
Yesterday I cycled through the ponderosa pine forests southwest of Penticton with a group of friends. There is a nice trail that winds up and down and around between White Lake and Mahoney Lake, generally following the course of Kearns Creek but avoiding the canyon (by climbing high above). Most of it is in the White Lake Grasslands Protected Area (a badly misnamed piece of land, since it doesn’t include White Lake, nor any grasslands to speak of). The forests in the first section have had a lot of thinning done over the past year, both for fire management purposes and to improve the habitat for the rare (and Endangered in Canada) White-headed Woodpecker. The ponderosa pine forests throught western North America have been radically changed in the last century since regular burning by native peoples stopped in the late 1800s, logging took out the big trees in the early 1900s (in this area the lumber was mainly used for apple boxes), and active fire suppression starting in the 1950s. Those three factors have resulted in a dense forest of young trees, quite a difference from the parklike stands of big, mature trees with an open understorey that was common before 1850.
I figured it was a huge long shot to hope for a White-headed Woodpecker, but I wanted to check a few owl nest boxes I’d put up along this trail in the late 1980s and hadn’t checked too often since the track was gated about 10 years ago. The first box was hanging upside down, so I’ll have to go back with a ladder, hammer and nails to fix that. Nobody answered the knock at the second box, but at the third box out popped a flying squirrel! She took a quick look at us, then glided out, landing on the leg of one of my friends, ran up her back, then took off for another tree nearby. I’m guessing it was a female squirrel, since most of the flying squirrels that use these boxes are females that build nests in the spring as a maternity home. The nests are invariably made of hair lichens in the Okanagan, while the ones I find in boxes on the coast are built of moss. In contrast, red squirrels always make their nests of grass in this area.
Most of the friends with me had never seen a flying squirrel, not surprising since the species is highly nocturnal. I usually see them only when I check my nest boxes, where they are one of the commonest occupants. I figure they occur in about the same numbers as the more conspicuous red squirrel, which is a species active in the day. Flying squirrels are easy to identify, even when just poking their nose out of a tree cavity or nest box hole, since they have big brown eyes adapted for their nighttime lifestyle. Once they’re out on a tree trunk, their wrinkly sides (which unfold into a large gliding surface when they jump), and long flat tail are distinctive.
Flying squirrels eat a lot of fungi, an important role in forests where fungi play a big part inthe growth of trees. Many of the fungi, especially the underground truffles, are intimately involved with tree roots, helping the trees take up water and nutrients. And flying squirrels make sure the fungi get spread around the forest.