Both tree squirrels and ground squirrels are common in the Los Angeles area. The main difference between these animals is where they nest, live, and hide from predators.

Tree Squirrels

Two species of tree squirrel often encountered in Los Angeles are the Western Gray Squirrel ( Sciurus griseus) , also known as the California Gray Squirrel, and the Eastern Fox Squirrel ( Sciurus niger ) .

The Western Gray Squirrel is about 22 inches in length with a large bushy tail edged in white. The coat can run from a “salt and pepper” to a silvery gray above to white below. They weigh in at between 1.5-2 pounds and lack any stripes, spotting, or flecking common to ground squirrels.

Western Gray Squirrels eat primarily acorns and supplement their diet with pine and other nuts, mushrooms, tender twigs and shoots, and grain.

Fox squirrels are the largest of the North American squirrels and can grow to 29 inches in total length, have a somewhat square head, bushy tail, and weigh 3 pounds. They usually have a light brown coat and a reddish or orange underside.

Fox squirrels are generalist feeders and their diet is dependent upon the area in which they are found. They feed heavily on nuts, flowers, seeds, tree buds, mushrooms, and cultivated crops. Animal food items include bones, bird eggs, nestlings, and frogs. Fox squirrels are classic scatterhoarders. They carry nuts in their jaws and bury them in various locations within their home ranges.

Tree squirrels are active during the day and are frequently seen in trees, running on utility lines, and foraging on the ground. Tree squirrels do not hibernate and are active year-round.

Tree squirrels damage green and ripe walnuts, almonds, oranges, avocados, apples, strawberries, tomatoes, and grains. Telephone and electrical lines are sometimes gnawed and they also chew on buildings or invade attics through knotholes or uncovered roof vents. Eastern Fox Squirrels can become some what aggressive and antagonize dogs and may frighten the elderly.

Tree Squirrels and Disease

Small rodents such as squirrels, rats, mice, hamsters, guinea pigs, gerbils, and chipmunks, rabbits and hares are almost never found to be infected with rabies and have not been known to cause rabies among humans in the United States. Bites by these animals are usually not considered a risk of rabies. Small rodents may also carry other diseases such as: toxoplasmosis, sylvatic (bubonic) plague, western encephalitis, encephalomyocarditis, murine typhus, tularemia, endemic relapsing fever, and ringworm, all of which are still very rare.

Do not handle or feed squirrels as they are wild animals and may bite. Tree squirrels are classified as game mammals by the California Fish and Game Code and can be controlled only as provided by hunting regulations (Section 4181).

Ground Squirrels

squirrelCalifornia Ground Squirrels (Otospermophilus beecheyi) have mixed gray, light brown, and dusky fur giving the upper coat a mottled appearance. A band of slightly darker fur, flecked with light gray, extends from the head over the middle of the back. Gray fur forms a cape over the sides of the head and shoulders. In contrast to the tree squirrel, their tail in long and thin.

California Ground Squirrels live in burrows. They eat a variety of seeds, fruits, acorns, roots, mushrooms, and insects such as: grasshoppers, crickets, and caterpillars.

California Ground Squirrels hibernate for several months of the year. In some areas, adult squirrels may spend as much as eight months dormant in their burrows.

Don’t let that cute face fool you!
The L.A. Department of Animal Services received 57 complaints about squirrels from 2002-2006. Ground squirrels damage many food-bearing and ornamental plants. Particularly vulnerable are grains, nut and fruit trees such as: almond, apple, apricot, orange, peach, pistachio, prune, and walnut. Ground squirrels will enter gardens and devour vegetables in the seedling stage. They may damage young shrubs, vines, and trees by gnawing bark, eating twigs and leaves, and burrowing around roots. Ground squirrels will gnaw on plastic sprinkler heads and irrigation lines. They also eat the eggs of ground-nesting birds.

The burrowing of Ground squirrels also can be quite destructive. Burrows around trees and shrubs can damage and desiccate roots, and sometimes topple trees. Burrows beneath buildings and other structures sometimes necessitate repair.

Ground Squirrels and Disease

Ground squirrels can harbor diseases harmful to humans, particularly when squirrel populations are dense. Do not touch or feed squirrels , no matter how cute they are.

A major concern is bubonic plague transmitted to humans by fleas carried on the squirrels. Ground squirrels are susceptible to plague, which has wiped out entire colonies. If you find unusual numbers of squirrels or other rodents dead for no apparent reason, notify public health officials. Currently, the plague in humans is relatively rare and can be successfully managed with antibiotics if contracted. Only 8 cases of the plague were reported in the State of California in the 1990’s.

Ground squirrels are classified as nongame mammals by the California Fish and Game Code. Nongame mammals injuring growing crops or other property may be controlled in any legal manner by the guardian or tenant.

Squirrel Control Tips

(Courtesy of the Brooklyn Botanical Garden Gardeners Resource Center).

1. Practice good sanitation and maintenance: Prevention is the best solution. Don’t leave companion animal foods out in the open. Cover garbage cans and barbecues. Prune branches six feet away from the ground and from the roof of your property. Repair construction gaps (with wood or sheet metal) to keep squirrels from making a nest in your attic.

2. Squirrel proof your trees and shrubs: Trees that are sufficiently far apart from each other can be squirrel-proofed by fastening a 12-inch-wide band of sheet metal around the trunks six feet from the ground. Some people completely cage-off their bushes and small trees before the fruit ripen. Others suspend aluminum pie plates from their woody plants, and dare squirrels to run the gauntlet. They often do.

3. Cage your bulbs: Before planting bulbs, set homemade or store-bought metal cages into planting holes. Alternatively, place a wire mesh over the entire bed once you’ve finished planting.

4. Use barriers for your flowers and vegetables: Various barriers-chicken wire, hardware cloth, 1- to 2-inch metal mesh-can be spread over the ground and cut to fit around plant stems. Or completely cover over newly planted vegetables with a chicken wire fence.

For more tips, visit the Brooklyn Botanical Gardens website at: http://www.bbg.org/gar2/topics/sustainable/2000wi_squirrel_tips.html


University of California Agriculture and Natural Resources Integrated Pest Management Online http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7438.html

L.A. County Department of Agricultural Commissioner/Weights & Measures http://acwm.co.la.ca.us/scripts/tree_squirrels.htm

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