Between the tall grasses of OURSpace, just behind the High Park Nature Centre, the busy movements of voles can be easily tracked, even during the frosty months of the year!
When the cold ground is without snow, you might notice small furry bodies scurrying between the OURSpace gardens or hear some rustling of dry Savannah plants, as the voles feed on seeds and bark.
However, once the ground becomes covered with snow, voles will retreat to the subnivean zone for protection from cold temperatures, intense winds, and hungry predators.
The subnivean zone is the area between the surface of the ground and the bottom of the snowpack. Under this snow, these tiny mammals will create long tunnel systems, which have air shafts to the surface above. During this time, you might notice tiny vole tracks in the snow or the subnivean air shafts.
It takes only about 15cm of snow for voles to have a sturdy snow roof over their heads and a good amount of space for them to reside and move freely within the subnivean tunnels.
Add another 5cm and the subnivean zone will remain within a degree or two of 0°C, regardless of the temperature and weather conditions in the outside world. In other words, the deeper the snow the better!
On your next visits to High Park, keep an eye out for sneaky voles, their tracks, and subnivean air shafts!