Ken Lake Wildlife

Although tree squirrels spend a considerable amount of time on the ground, unlike the related ground squirrels, they are more at home in trees. Washington is home to four species of native tree squirrels and two species of introduced tree squirrels. The following information is a condensation of the Living with Wildlife article on tree squirrels.

The Douglas squirrel, or chickaree is approximately 10 to 14 inches in length, including its tail. Its upper parts are reddish-or brownish-gray, and its underparts are orange to yellowish. When you see the fir cone parts scattered on the ground, start looking for a Douglas squirrel.

The Northern flying squirrel is the smallest tree squirrel in Washington, measuring 10 to 12 inches in total length. It is rich brown or dark gray above and creamy below. Its eyes are dark and large, and its tail is wide and flat. These nocturnal gliders are surprisingly common, yet are seldom seen in their forest homes throughout the state. Consider yourself lucky if you see a flying squirrel, because they are very cute!

The Eastern gray squirrel were introduced in Washington in the early 1900s. They are now the most common tree squirrels in our community.

The upper parts of the Eastern gray squirrel are gray with a reddish wash in summer; its underparts are whitish. It’s about 20 inches long, half of which is its prominent, bushy tail.

The increasing number of introduced Eastern gray squirrels is often said to be responsible for the decrease in Douglas squirrels in certain areas. However, given that these squirrels have different food and shelter preferences, it’s more likely that increased home construction and other development, and loss of coniferous forests is responsible for any decline in Douglas squirrel populations.

Calls
The Douglas squirrel will announce an intruder’s presence with much intensity. This territorial call sounds something like a rapid tsik tsik tsik, chrrrrrrrr—siew siew siew siew. The call of the Eastern gray squirrel— que, que, que, que—is usually accompanied by flicks of the tail. It makes other calls as well, including a loud, nasal cry.

The call of the relatively silent flying squirrel is a quiet, high-pitched, birdlike tick tick.

Food and Feeding Habits

In the fall, when Douglas squirrels are actively harvesting and storing food for winter, look for “cuttings” under coniferous trees. Cuttings are made because cones containing seeds, grow at the end of fragile, easily broken twigs. The squirrels find that the easiest way to harvest them is to nip these twigs off the parent branch. The squirrels then climb to the ground, harvest the cones, or carry it off to a storage site.

Squirrels store food and recover it as needed. Hollow trees, stumps, and abandoned animal burrows are used as storage sites; flowerpots, exhaust pipes, and abandoned cars are also used.

In winter, holes in the snow may indicate where squirrels retrieved stored food. Tree squirrels feed mostly on plant material, including seeds, nuts, acorns, tree buds, berries, leaves, and twigs. However, they are opportunists and also eat fungi, insects, and worms.

Scientists credit flying squirrels with helping forest health by spreading species of fungi that help trees grow.

Flying squirrels can glide 150 feet or more from a height of 60 feet. They don’t actually fly, but glide downward through the air using skin flaps that stretch between their front and rear legs, forming two “wings.” The tail is used as a rudder to help them keep on course.
(From Christensen and Larrison, Mammals of the Pacific Northwest: A Pictorial Introduction.)

Nest Sites

Tree squirrels construct nursery nests in hollow trees, abandoned woodpecker cavities, and similar hollows. Where these are unavailable, they will build spherical or cup-shaped nests in trees, attics, and nest boxes.

An alternate nest may be constructed in a tree for summer use. In urban areas, squirrels mostly nest in buildings and other structures. Nests contain leaves, twigs, shredded bark, mosses, insulation, and other soft material.

Life Cycle

Depending on the species, tree squirrels mate from early winter to late spring. One litter of two to four young is produced from March to June.

At about 30 days of age, the young are fully furred and make short trips out of the nest. At about 60 days of age, they begin eating solid foods and venture to the ground. At about three months of age, juvenile squirrels are on their own.

Squirrels are relatively safe, except for an occasional owl or goshawk. On the ground, large hawks and owls, domestic cats and dogs, coyotes, and bobcats catch squirrels. Vehicles, disease, and starvation also kill squirrels. Most squirrels die during their first year; if they survive that, they live three to five years.

Tips for Attracting Squirrels

o Include trees and shrubs that provide seeds, nuts, acorns, cones, and fruits at different times of the year.

o Leave some tree or shrub prunings on the ground for squirrels to gnaw on during winter.

o Install a feeder and a nest box suitable for squirrels. (Several flying squirrels will use a duck or owl box for hibernation, and an individual female will use a small box for raising her young.) Be careful when monitoring or cleaning these boxes, because any rodents could carry Hanta virus, which could infect you if dust from dried droppings and urine gets in your eyes, nose, or mouth.

Preventing Conflicts

o Don’t feed the squirrels. Tree squirrels eat most types of birdseed and relish sunflower seeds. Once accustomed to a food source, they will be persistent at finding ways to reach it.

o Another way to discourage squirrels from eating birdseed is to offer birds foods that squirrels do not like. Mixing dried pepper flakes into birdseed makes it less attractive to squirrels. (Give the seed a quick spray of Pam or other oil before mixing so the pepper flakes stick to the seed.)

o Keep squirrels out of birdhouses. Tree squirrels sometimes raid eggs or small nestlings in nest boxes for food.

o Protect garden bulbs, plants, and seeds. Newly seeded areas and seedlings can be covered with a temporary wire cage or netting made from 1-inch mesh chicken wire.

o Protect tree bark from being stripped or eaten. Tree squirrels strip the stringy bark strands from redwood, red cedar, and certain other trees to line their nests. Pepper spray or a commercial taste repellent such as Ropell® can be applied to the bark to prevent bark removal. Applications will need to be repeated in damp weather. A problem at Ken Lake is chewing of bark from the top side of big-leaf maple trees. Gray squirrels have the habit of chewing away the bark then returning to eat the sweet sap from the maples. With the bark removed, the limbs start to rot on the top side weakening them. The weakened limbs break during storms or from heavy loads of leaves in late summer.

Resolving Conflicts

Should you need to remove a squirrel from your attic, a wildlife damage control company can be hired (see Hiring a Wildlife Damage Control Company). You can also do the work yourself by following the steps listed under Evicting Animals from Buildings. Because attics can be difficult to access and maneuvering around in them can be dangerous, it is recommended that a professional be hired when attics are involved.