Fox squirrel or gray squirrel: the question that changes the rules
California treats tree squirrels as game mammals, and the practical consequence in San Diego is that two animals that look broadly similar sit in different legal categories. UC IPM explains that eastern fox squirrels damaging property may be controlled at any time. Gray squirrels are not covered by that allowance, and controlling them requires a depredation permit from California Fish and Wildlife. This is not a technicality you can leave to the crew after work has begun. It determines whether trapping is available to you at all, and a company that cannot say which species it identified and how has not done the first part of the job. There is a way around the problem for most homeowners. A one way door removes the animal without taking it, so it works regardless of which species is using your attic. In a region where introduced and native squirrels overlap, that is a good reason to prefer exclusion over trapping and to be wary of any quote that leads with a trap count.
Canyon slopes and what burrows do to them
San Diego builds on graded pads next to canyons, and that geometry puts ground squirrel habitat directly against structures. What makes it serious is scale. UC IPM reports that burrows usually run five to thirty feet in length and two to three feet deep, sometimes reaching six feet. A system that size moves a lot of soil. On a slope, that shows up as settling behind retaining walls, voids under hardscape edges, and erosion channels that widen with each wet season. In a city receiving only about 10 inches of rain a year, the damage accumulates quietly and then appears all at once after a storm. Timing matters for the response. Adults are active mid January through October, with fumigation suited to February through June and baits appropriate from June through October, so the month you call affects what can be done. Ask a provider which method fits the current season and what licensing they hold, since ground squirrel work done for hire in California requires it.
Where tree squirrels get into a San Diego house
Rain does not do the preparation work here. With about 10 inches a year, exterior wood stays comparatively hard, so entries are usually gaps that already existed rather than rotted holes an animal opened from scratch. The list is short and specific. Attic, gable, and eave vents with light screening are first, because the screen that came with them is not built to resist teeth. Tile ends and the space beneath tile come next on the roofs that have them. Then the junctions where a lower roof meets a wall, and the flashing around vent stacks. Solar equipment deserves its own look. The shaded space under a rooftop array is a sheltered nesting spot with wiring running through it, and unprotected conductors are a real hazard. If your roof has panels, ask specifically whether the quote covers screening the array perimeter, and check whether that work needs to be coordinated with the installer so the equipment stays under warranty.
A San Diego calendar for both problems
Two calendars run side by side on a property that has both animals, and they do not line up. For tree squirrels, UC IPM describes one or two litters a year of three to five young, with breeding in late winter or spring. That makes the spring months the period when an attic may hold young and sealing has to wait for an inspection. Damage from food caching peaks in fall, which is also the best stretch for roof repairs, since nothing is nesting behind the work. For ground squirrels, adults are active mid January through October and breeding runs February through June. Fumigation suits February through June, while baits are effective from June through October, so the method depends on when you call. Put together, that gives a rough plan for the year: handle slope work inside the active season with the method that fits the month, and do attic exclusion and roof sealing in late summer and fall when the litters are past and caching pressure is climbing.
What drives the price on a San Diego property
The first question is how many problems you are paying to solve. An attic job and a slope job are separate scopes with separate methods, and a quote that blends them into one number is hard to evaluate. On the building, the count of openings drives the cost, followed by roof type. Sealing tile ends is slower than screening a run of plain vents, and working around a solar array adds coordination as well as labor. Damage adds a layer: chewed wiring means an electrician, and soiled insulation has to be removed and replaced rather than raked back into position. On the slope, cost tracks the size of the burrow network and how much of the January to October active season is left when you begin. Ask for removal, roof sealing, attic cleanup, and any ground work as separate lines. With median home values near $880,000 in San Diego, the sealing line is what protects the asset, and it is the last place to accept the cheapest option.
How to compare two quotes here
Begin with the species. A quote that names the animal and explains how it was identified is worth more than one that says squirrels, because in California that identification decides whether trapping is even permitted without a depredation permit. Second, compare the count of openings and the materials. Quarter inch hardware cloth, fitted metal closures, and proper flashing hold up. Sealant, foam, and factory vent screen do not, and in a dry climate they fail from sun and brittleness as readily as from teeth. Third, look for the timing question. An operator who raises the litter period without being prompted has done spring work before. Fourth, if burrows are part of the job, ask which method they plan and whether the month supports it, plus what license they hold for that work. Finally, check what happens to insulation and whether the return visit to pull the one way door and close the opening is included. That visit is where the job actually ends.