OBSERVATION: This observation was originally made by Dr. Jeff Bowman, a population ecologist from the Ministry of Natural Resources, and Dr. Paul Wilson, a wildlife geneticist from Trent University.
Over the past 10 years these researchers have witnessed the arrival, and continuous increase, of the Southern flying Squirrel (Glaucomys volans) to the forests of the Kawartha Lakes district of Ontario (See Figure 1).
Originally the southern flying squirrel occupied most of the Eastern United States – ranging from Florida up to the base of Lake Erie. However, following a succession of unusually warm winters the southern flying squirrel has expanded its territory northward by over 200 km into the Kawartha Lakes area just below Algonquin Park. This has created a zone of habitat overlap with the indigenous Northern Flying Squirrel (Glaucomys sabrinus) (See Figure 2). The northern flying squirrel is much larger than its American cousin – with the average adult male weighing in at roughly 90 grams (See Figure 3), compared to the southern’s 65 grams (see Figure 4). The two can be easily distinguished by their belly fur; with the northern having two-tone belly fur that is white at the tips and grey at the base, whereas the southern’s belly fur is strictly white.
It will be interesting to observe whether there will be direct competition between the two species in this zone of habitat overlap. Both species are active over the winter - as they do not hibernate; and both seek out tree cavities to make their nests in. Even with its smaller size, it appears that the southern flying squirrel is more aggressive than the northern. Therefore, if tree cavity numbers become a limiting factor – the southern may have an advantage if competition for these nesting places take place.
It has also been documented that the two species are even cross-breeding in this zone of habitat overlap - with roughly 4% now hybrid. The major ecosystem role of these squirrels is as seed dispersers. Only time will tell if this habitat change, and subsequent hybridization phenomenon, is a positive reaction/adaptation to climate change – or detrimental to both squirrel species and the environment.
Additional Resources:
A look at Dr. Bowman’s research on the episode Night moves of the Love Nature series Great Lakes Wild
The Kawartha Flying Squirrel Project
Hybridization of the two species
Facts about flying squirrels
Consultations:
Dr. Jeff Bowman
Dr. Paul Wilson
Dr. Gary Burness
Figure 1: Kawartha Lakes Area near Peterborough Ontario (Taken from Google Maps).
Figure 2: Flying Squirrel Range in North America (Taken from Canadian Geographic website).
Figure 3: Northern Flying Squirrel (Taken from Canadian Wildlife Federation website).
Figure 4: Southern Flying Squirrel (Taken from mewondersofnature.com).
Observations From Members 