Members of the squirrel family (Sciuridae) include tree squirrels, flying squirrels, ground squirrels, chipmunks, prairie dogs, and woodchucks (marmots).

In San Diego County, ground squirrels are in the majority. All are primarily vegetarian, eating roots, stems, bark, shoots, leaves, flowers, fruit, and nuts from a wide range of plants.

Some include a few insects in their diets. Most have long, cylindrical bodies with large bushy tails that provide balance and slender toes with sharp claws that aid in climbing.

The burrowing species (ground squirrels, prairie dogs, and woodchucks) have strong front paws and short tails.

Squirrels are known for their tendency to hoard seeds and other food either in their nests or in caches nearby. Squirrels often store more than they need and lose or forget where it is stored; in doing so, they help scatter seeds to take root and grow in new locations.

Ground squirrels (Spermophilus ssp.) are 16 to 19 inches long, including the bushy tail, and weigh 1 to 3 pounds. Their coloration is grayish brown with buff flecks. They have short ears and legs and strong front claws. Litters range from two to eight.

Squirrels have powerful, gnawing teeth for eating tough vegetable matter, and they can close their mouths while leaving their front teeth exposed for digging.

Their other distinguishing feature is that their teeth never stop growing. They must continue gnawing to wear them down so that (1) they can close their mouths (otherwise they would be unable to take in food and would eventually starve) and (2) the teeth do not grow into their skulls, eventually killing them.

The den of the ground squirrel is an intricate burrow with several entrances.

Primarily herbivores, ground squirrels eat plant material, including wild fruit plants, seeds, succulents (such as ice plant), and grasses. They also prey on insects, the eggs and young of ground-nesting birds, and, occasionally, small mammals. They eat much food where it is found but also carry seeds in cheek pouches to build up large stores underground.

Ground squirrels are active during the day and sleep at night. Southern ground squirrels do not truly hibernate but remain inactive in their burrows in winter. Ground squirrels are not as social as prairie dogs but may group together and live in large colonies where food is abundant. They live from 5 to 12 years.

Squirrels are often prey for large carnivores such as coyotes, owls, and bobcats, but their main enemies are humans and automobiles. Destruction of woodland habitats for development adversely impacts squirrel populations.

The ground squirrel's chief enemies include foxes, weasels and hawks. Its primary defense is sighting an approaching predator at a great distance and escaping to the protection of its burrow.

Tips

1.  Squirrels rarely do significant damage to plantings, so try to determine the real culprits. Because squirrels are active during the day, it is relatively easy to observe whether they are feeding on your garden or fruit trees. If the damage occurs at night, squirrels are not at fault.

2.  Because squirrels are such excellent climbers, fencing is not a particularly effective control. One way to protect trees is to wrap a 2- foot band of sheet metal around the trunk about 6 feet off the ground. Trim any branches below 6 feet. Also, make sure no other trees are close enough to provide jumping access. Some taste repellents applied to the food source may be effective; be sure to follow instructions carefully.

3.  Squirrels will readily take up residence in a building if access is available. It is important to block all holes with wood or wire mesh to prevent entry. To remove a squirrel from an attic or other similar space, do the following:

• Block the entry and set a live trap baited with peanut butter, fruit, or nuts.
• Remove the captured animal in the trap immediately and release it at a different location with suitable habitat at least 5 miles away.
• Be careful not to block holes if young are still inside. Adult squirrels can cause significant damage gnawing to get back inside to their young. If a hole is blocked, open it long enough for the adult to rescue the young; then cover it again.
• Remember that live-trapping is not a final solution. Be sure to close all possible access areas to prevent repopulation.

4.  Prune overhanging tree limbs, shrubs, and vines that may provide access to attics and other areas. Cover telephone and electric wires near the house with long plastic tubing to discourage use of the wires for entrance and exit.

5.  Squirrels are excitable and can cause severe damage if trapped inside a home. When badly frightened, they tend to run recklessly in circles and will knock over anything in their way. Quickly and quietly open a door or window to the outside and leave the room. The squirrel wants out as much as you want it out and will leave as soon as the threat of your presence is gone.

6.  A squirrel may fall in a chimney while climbing on the roof. Do not remove the squirrel through the fireplace as it may escape into the room. Secure a heavy rope from the top of the chimney and drop it down to the fireplace. The rope provides a perfect escape route during daylight hours. After the squirrel has exited, remove the rope and properly cap the chimney. If a squirrel is trapped behind a fireplace screen or doors and is unable to exit up a rope, carefully set a live trap baited with peanut butter inside the fireplace.

7.  Easily accessible bird feeders provide a source of food for squirrels. Install only free-standing (not hanging) bird feeders in sites where squirrels cannot get access; keep them away from shrubs and overhanging tree limbs. Put the feeder on a metal pole at least 6 feet high. Attach a metal cone to the pole to prevent squirrels from climbing up it. Hanging feeders are not recommended, because squirrels can climb down the hanger line or shake the line until food falls to the ground.

Do not attempt to handle squirrels. Any handling of these excitable creatures causes intense stress. When releasing a live-trapped squirrel, avoid touching it, and wear gloves and long sleeves to prevent contact with any squirrel parasite. Place the trap on the ground, open the door, and allow the squirrel to exit on its own.

Information provided by WildCare Terwilliger Nature Education & Wildlife Rehab, San Rafael, CA

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