Which of the four animals is it, and how you can tell
Position on the property does most of the identification work before anyone climbs a ladder. Overhead noise almost always means raccoon here, because it is the one strong climber among the four common species. The sound is heavy and unhurried, with pauses, and it starts well after dark. Raccoon entries look pulled apart rather than gnawed, since the animal has dexterous hands and can lever a vent screen out of its frame. They also establish one latrine and return to it, so droppings pile in a single spot instead of scattering. Ground-level odor with silence above you points to a skunk or an opossum. Neither climbs, so the absence of attic noise is information rather than a puzzle. Look at the base of exterior stairs, the edge of a deck and the crawlspace access panel. Holes in the yard with nothing in the building means California ground squirrels. The entrances are small, roughly a couple of inches wide, and they cluster. Write down what you observe before you call anyone. A company that arrives and independently describes the same evidence is a company that is actually reading the property.
What California's relocation rule really changes
The single most useful thing to understand before you hire anyone is that moving a caught raccoon is not a routine option in this state. It is prohibited without written permission from the Department, and furbearer seasons are set at the state level rather than by whoever owns the truck. That rule quietly settles a lot of arguments. If an animal cannot lawfully be driven away and released, then catching it does not, by itself, end anything. The building is still open, the food source is still there, and the neighborhood still holds other raccoons. A company whose entire proposal is a number of trap nights is selling you a temporary vacancy. The rule also gives you a clean screening question. Ask what happens to an animal after it is caught, and listen for whether the answer is specific. Operators working within the framework will explain their approach directly, including the unpleasant parts. Vague reassurance is the answer to avoid. Exclusion avoids the entire question. An animal that walks out through a one-way device was never captured, so no permission is required and nothing sits in a cage.
Ground squirrels and the concrete you are standing on
The costliest wildlife damage on many San Francisco properties is invisible until something moves. California ground squirrels build extensive tunnel networks, and they prefer edges: the seam where soil meets a walkway, the base of a retaining wall, the perimeter of a patio slab, the footing of a set of steps. What you notice first is a cluster of small entrance holes, usually a couple of inches across, sometimes with a fan of loose soil. What you do not notice is how much material has been carried out from underneath the adjacent hardscape. Soil is load-bearing. When enough of it leaves, the slab above loses support, settles unevenly, and cracks. By that point the wildlife portion of the problem is the smaller line item. Repairing a settled walkway or a leaning wall is masonry work with its own budget. Control is a program rather than an event, involving repeated visits and attention to the whole burrow system. Closing visible holes on their own achieves nothing, because the network has other exits. The prevention half is landscaping: keep dense ground cover trimmed back from paved edges so a squirrel cannot dig under cover.
Why moisture, not cold, is the local building failure
In most of the country wildlife entry points get made in one of two ways: an animal chews through, or an animal forces something that froze and cracked. Neither describes what happens here. The local mechanism is slow saturation. Average humidity near 75 percent means exterior wood rarely dries out completely, even in a city that only records about 24 inches of rain a year. At 52 feet of elevation with marine air moving through constantly, the surfaces that stay wettest are the ones nobody inspects: the back face of a fascia board behind a gutter, the underside of a soffit, the end grain where a rafter tail is cut, the sill of a crawlspace vent. Softened wood fails differently from rotten wood. It looks intact and holds paint, but a screw driven into it has nothing to grip. That matters enormously for the repair, because a metal patch fastened to punky trim will loosen within a season or two, and then you are paying twice. So the question to put to any company is direct: does this price include replacing compromised wood before sealing, or is the patch going onto whatever is already there?
The year here, and when to schedule the work
There is a rhythm even without real seasons, and knowing it keeps you from paying for the wrong month. Spring is litter season along this coast and the most expensive time to start. A female settles into a defensible cavity, and the giveaway is that activity stops following a clock: noise spreads across the day instead of clustering after dark. Installing a plain one-way device then removes the mother and strands the young, which is both cruel and costly to fix, so the job becomes hands-on removal with a reunion box. Autumn brings a den-seeking stretch, milder than the version colder cities get, but real. Animals that spent the year outdoors start testing structures, and small openings become occupied. Between those two windows, activity never truly stops, because winter lows near 46F give nothing a reason to move on. The scheduling advice that follows is simple. Late summer through early autumn is the best time for exclusion work in San Francisco: young are independent, the weather cooperates with roof access, and the repairs land before the den-seeking wave rather than after it.
Comparing two quotes without a coin toss
Two bids on the same building can differ by a wide margin, and the reason is rarely the hourly rate. It is what each one quietly left out. Start with the opening count. A quote that names a price without listing where the animal is getting in has skipped the inspection, whatever the visit felt like. Ask for a numbered list with photographs, then compare the two lists side by side. If one company found four openings and the other found one, that is not a pricing difference, it is a thoroughness difference. Next, the material at each opening. Metal flashing and hardware cloth behave differently over time from expanding foam and a painted wood patch, particularly in air this damp. Third, the return visit. One-way devices have to come off, and somebody has to seal behind them. Confirm that trip is inside the number. Fourth, cleanup. Contaminated insulation removal is often a separate line, which is fine as long as you know before you sign. Last, ask what happens if something is back inside thirty days, and get the answer in writing rather than as reassurance on a doorstep.