There are 3 types of squirrels in San Diego. The most common is the California Ground Squirrel, Western Gray squirrel and the non-native, Eastern Fox squirrel (tree squirrel)
The ground squirrel is the only species that makes its home in burrows dug underground. They may live communally but each squirrel has its own entrance.
Most squirrels are active during the day, beginning at dawn, often resting midday, and active again until dusk.
Squirrels are most active during the fall, collecting and burying nuts and seeds and also looking for protective shelter from winter weather.
Tree squirrels breed and have their young in late winter, early spring
Ground squirrels breed in early spring and have their young in late spring and early summer
Squirrels store food in their cheek pouches and cache(hide) food in areas near their den to recover later.
They are primarily herbivores eating plants, seeds, nuts and fruits.
They are preyed on by a number of species but are skilled at deterring rattlesnakes with a particular tail swish.
Ground squirrels have been known to chew the shed skin of a rattlesnake, lick her fur, then rub it on her babies to keep the snakes from picking up the scent of her babies.
Many people consider squirrels a nuisance, but they have been introduced by scientists into burrowing owl territory to help create burrows that entice the birds back to their habitats and keep the grasses low.
They have also been known to spread seeds that have helped many farms produce more crops.
Ways to Discourage
Young squirrels are with their mother until fall so it is best to leave them alone until late fall or winter if you are trying to exclude them from a structure.
To protect bulb plants- Blend bloodmeal into the soil around the bulbs to deter squirrels from digging and eating the bulbs. Plant covers are also effective against squirrel damage to bulbs. A diluted solution of hot sauce (one tablespoon hot sauce to one gallon water) misted on the soil and bulbs is another effective deterrent.
To protect bird feeders- Commercial bird feeders will potentially discourage them from the feeder, but they will still pick up anything that drops and stay around for that.
Bird feeders should also be placed 8 ft away from tree branches to prevent them from jumping over to them.