JACKSON, Wyo. — Early winter is not a time to slow down for the American red squirrel. The species is too busy defending their pinecone stashes from other opportunistic seed predators.
This tree squirrel has a bushy red tail with hints of a white outline, and a thick, white circle surrounds its black eyes. One of three species of “tree squirrels,” the American red squirrel is the only native member of the genus Tamiasciurus or “pine squirrels” to be located and abundant in Wyoming, according to the Wyoming Game and Fish Department.
Red squirrels are active all winter and will stay up to defend their cone stashes vociferously for winter survival. Many species of birds, other red squirrels and small mammals such as chipmunks, voles and mice can snatch a coveted supply of red squirrel pine seeds.
According to the Jackson Hole Wildlife Foundation (JHWF), red squirrels harvest pinecones and store them as large middens – stores of thousands of cones – which are buried in the cool, moist ground to keep the seeds fresh. Middens can be found at the center of the most productive group of trees. Squirrels eat cones like corn-on-the-cob, scattering scales everywhere while consuming the nutritious seeds. It has been calculated that squirrels consume 50 to156 cones a day and stash tens of thousands of cones in a midden in a good year.
These stores of cones can last several years, so when squirrels die, others can inherit the stashes. Red squirrels are unique in that they leave behind their hard-worked-for bounty.
“If you happen to settle on a territory previously owned by a male or prime-aged squirrel that happened to die in the best of their life, you fall into this tub of butter and inherit all these resources,” Associate Professor Andrew McAdam said via The Wildlife Society website. “Squirrels are unique because they leave behind this extension of resources, whereas other species like bison, which store energy as body fat, can’t leave it behind when they die.”
JHWF states via their website that these winter residents balance energy by resting in warm, protected locations, and then will dash about to find food to add to their reserves. Nesting sites are vital for thermal regulation. Tree squirrels prefer natural cavities, but some will build nests of leaves and grass 12 to 60 feet off the ground. Some will also burrow into tunnels under their middens for warmth and safety.
Vocally territorial, these squirrels can be heard chattering loudly at any perceived threat, and will bark to mark their territorial boundary.
According to JHWF, squirrels have different calls depending on whether or not a threat is aerial or terrestrial. One study indicates that red squirrels produce a high frequency, short “seet” sound similar to alarm calls of birds. This sound is hard for raptors, such as goshawk, great horned owl, or red-tail hawk, to locate or hear. A louder bark call is used for overland threats, such as a pine marten, weasels or fox. Once alerted, squirrels scramble and hide in dense vegetation.
The Wyoming Game and Fish Department considers the red squirrel as a keystone prey species relied upon by a number of other species ranging from goshawks, long-tailed weasels, great gray owls, martens and lynx.
Between predation and starvation, only 25% of squirrels survive into their second year.
