The Eastern Fox Squirrel at Deer Flat NWR
by Bob Christensen
My observations: I have regularly observed Eastern fox squirrels (Sciurus niger) in the riparian (or lakeside) cottonwood forests surrounding Lake Lowell. Most often, I have watched these furry arboreal rodents scurrying along the branches and up and down the tree trunks; or perched high above while chattering their displeasure at my intrusion into their serene habitation. In the wintertime, I have spotted their solitary leafy nests (called “dreys”) attached to high leafless limbs, sometimes several nests in one tree. I have also found them commonly nesting in wood duck boxes on the Refuge.
Range: The fox squirrel is not native to Idaho. Its natural range extends over certain portions of southern Canada, eastern United States and northern Mexico. Meanwhile, introduced populations of the Eastern fox squirrel occur in southern reaches of Canada as well as in several western states, including southern Idaho. While fox squirrels prefer open woodland with open understory and scattered cover of trees, they also are found in urban areas where mature trees have been established.
Description: The Eastern fox squirrel is a comparatively large rodent with a long and bushy tail. The scientific name of this species is “niger” (black), since the first Eastern fox squirrel to be described had a black coat. The Eastern fox squirrel is so called due to the common yellowish-red coloration (especially on its bushy tail), closely resembling that of a red fox.
Habits: These rodents are daytime foragers that are active throughout the year. Nests are used as daily shelters and sites for raising their “kittens.” Their major forms of communication are scents and vocalizations, as well as tail and body postures. Vocalization includes a wide variety of barks. They typically use a chattering sound as an alarm call, whereas a tooth chattering serves as a display of aggression.
Eastern fox squirrels are omnivores, they generally feed upon plant matter and gall insects, including moths, beetles, bird, eggs, and dead fish. They complement this diet with whatever seeds and nuts that are available.
Mating & Reproduction: Eastern fox squirrels have a promiscuous mating system, where individuals of both sexes have multiple mates. However, males usually compete for their mating right. These rodents have two defined breeding seasons, one in winter and another in late spring. However, females generally yield only a single litter each year. Newborn babies are naked and cared for by their mothers. When leaving the nest to forage for food, the female covers her offspring with nesting material.
Threats to the species: Nationwide, this species is threatened with loss or modification of its natural habitat, which has resulted in sharp population declines. Also, this rodent is commonly hunted in the eastern states. In urban areas, “roadkill” is a major cause of mortality.
Ecological Niche: On one hand, feeding on a wide variety of seeds and nuts, the Eastern fox squirrels have a huge impact on the ecosystem of their range, helping in the distribution and survival of many plants. This is largely due to their habit of storing food items: burying seeds underground, they often forget them. As a result, many of these seeds consequently sprout. One the other hand, because of being common and widespread throughout their range, these animals are a key prey species for raptors and a variety of terrestrial predators.
- One of the most unusual facts about this mammal is that it has pink bones; whereas bones on most mammals are white. This is due to accumulation of specific chemicals in its teeth, bones and tissues.
- Due to its extremely flexible ankle joints, the feet of this animal rotate up to 180 degrees, and the squirrel can climb down trees head-first.
- The squirrel is a Native American symbol of trust, thriftiness and preparation.
- The name “squirrel” originates from a Greek word “’Skiouros” that means a “shadow tail.”
- The four front teeth of this animal grow continuously throughout its life. In order to wear down old teeth, these rodents must gnaw on nuts and tree bark.
- When threatened or alarmed, squirrels try to confuse a predator by running back and forth and in various directions.
- Squirrels are also highly intelligent creatures. In order to confuse and get rid of food thieves, they occasionally pretend to bury nuts.
1. Eastern Fox Squirrel Wikipedia article: https://en.wikipedia.org/wiki/Fox_squirrel
2. Eastern Fox Squirrel on The IUCN Red List site – http://www.iucnredlist.org/details/20016/0