January 11, 2008
By Susan Benson
Director of Education
Cable Natural History Museum
There is a red squirrel that I see every day in my yard. He sneaks out from the cover of the wood pile and makes his way toward the bird feeder. Now that there is snow, he is especially interesting to watch because he has created a series of tunnels that he uses to get from place to place. He will appear near the trees, disappear and then pop up near the bird feeder, disappear again and pop up at intervals between the bird feeder and the house where he feeds on the sunflower seeds that have fallen from the window feeders. He does all of this while keeping a wary eye out for the dog, who will chase him every chance she gets.
The red squirrel is not only the smallest North American squirrel, but it is the only one to display any seasonal change in its pelage, or fur. In summer, the red squirrel is a grayish color above and white below. A prominent black line along each side separates the gray from the white. In winter, the red squirrel takes on a broad rusty red stripe down its back, from head to tail, and the black lines along the sides disappear. It also grows tufts of hair on the top of each ear, which then disappear when the warmer months return.
Unlike many squirrels that hibernate for the winter, red squirrels are active all year long. They mate in February and March and 3-7 young are born in April and May. Young squirrels stay with the adult female until they are 6-7 weeks old, and they reach breeding age in their second year (about 10-12 months old). The average squirrel life span is 2-3 years. They are preyed upon by coyotes, owls, martens, fisher, bobcat, and large hawks, and they are often the unfortunate victims of failed attempts to cross roads.
Red squirrels are remarkable dispersal agents for many trees and fungi because they cache their food. Red squirrels feed on seeds found in jack pine and white spruce cones, as well as acorns and many types of mushrooms, including species that are poisonous to humans. During the late summer and fall, I have watched red squirrels throw pine cones from the tops of the trees, each one clunking onto the driveway. The squirrel then comes down and makes small piles of cones at the base of the tree, while others are taken and buried elsewhere, preferably in a moist location. Moist soil keeps the green, unopened cones from drying out, opening up, and spilling their seeds. Mushrooms are cut off at the base of the stem and put up in the crotch of a tree to dry.
How do they find their buried treasures? Research has shown that red squirrels use both memory and smell to relocate their food stores. In fact, red squirrels have demonstrated the ability to smell a cache of cones under 12 inches of snow! You can tell where they have been eating by the presence of middens. These are piles of cone scales and the cone “stalks” that are formed when the squirrel returns to eat seeds from the cones and discards the inedible parts in the process.
Another interesting food source for red squirrels is the sap of paper birch and sugar maple. The squirrels acquire this food in the spring when Yellow-bellied Sapsuckers have returned and are drilling new holes in paper birch trees. The squirrels themselves gnaw gashes in sapling sugar maples to get the sap running. They return later to lap up the sweet liquid, which, by virtue of being exposed to the air that evaporates the water content of sap, has increased its sugar content from a mere 2% to a energy-rich 55%. These gashes heal themselves by July, causing no permanent damage to the trees.
Of course, red squirrels can be troublesome if they get into your attic or other buildings. They will chew on wood and cardboard and anything else they can eat or use to build a nest, and they can be very defensive when cornered. Red squirrels are feisty creatures. The one that eats at my bird feeders often climbs up on to the bottom edge of the window and looks into the dining room. This causes the dog to jump up and run her nails down the glass and across the inside sill, a secondary form of squirrel damage, I suppose. Never the less, the red squirrel is a joy to watch in all seasons of the year, and I suspect the dog enjoys having this little bundle of energy around as much as I do.
Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at www.cablemuseum.org to learn more about exhibits and programs.