Why are ground squirrels such a concern around Natomas and West Sacramento?
UC IPM says ground-squirrel tunnelling weakens levees, canals and earthen dams and is the biggest threat to California levees. Natomas and West Sacramento sit behind levees, so burrows on or beside embankments are a public-safety matter that belongs to the agencies that manage them. Burrows in your own yard are yours to deal with.
The Natomas Basin is bordered by the Sacramento and American rivers and is protected by about 43 miles of levee, and West Sacramento sits beside the Yolo Bypass. If you see burrows on a levee slope, a canal bank or other public embankment, report it to the agency that maintains it rather than treating it yourself.
What we handle is private land: the lawn, the lot, the commercial site and the property line where grass meets open ground. Neighbors with open fields or unmaintained lots often feed the problem, so a technician will look past your own fence.
How do I tell ground squirrels from voles, gophers or rats?
Ground squirrels leave open holes about 4 to 6 inches wide and are seen above ground in daylight. Voles leave small round openings joined by grassy runways and rarely show themselves. Gophers push up fan-shaped mounds and plug their holes. Roof rats climb and nest above ground. A technician confirms the animal before choosing a method.
Getting the animal right matters because methods do not transfer. A trap line that works on squirrels does nothing for voles under ivy, and a vole fix in thick ground cover will not touch a squirrel colony at the back fence.
If the noise you hear is in the attic rather than the lawn, you are probably looking at roof rats or other rodents indoors, which are handled differently.
What damage do ground squirrels and voles actually cause?
Ground squirrels undermine soil beside slabs, patios and fences, chew irrigation lines and strip garden plants. Voles gnaw bark and roots, which can kill young trees and shrubs. Both leave a patchwork of holes and runways that is hard to mow and can be a tripping hazard for children and pets.
Damage is rarely dramatic in a single week. It builds as burrow systems grow, and the first time most owners notice is when a section of lawn sags or a young fruit tree stops leafing out.
A burrow beside a patio or driveway deserves attention sooner. Soil loss under a slab can open a void that grows with every irrigation cycle.
- Soil settling beside slabs, walkways and block walls
- Girdled bark and dying shrubs or young trees
- Chewed sprinkler lines and drip tubing
- Eaten vegetables, flowers and ripe fruit
When is the best time of year to deal with them?
Late winter through spring is a common window, because squirrels are active on open grass from April and wet winter ground makes burrows easy to see. Summer's dry heat and hard-baked soil can make tracking harder. Any season works if there is fresh activity, and waiting usually means a larger burrow system.
Sacramento has a long dry summer and a wet winter, with rain concentrated from November through March. That rhythm shapes what you see: saturated ground in January and February can expose fresh dirt, while grass that has browned by August hides runways until irrigation greens it up again.
Our Sacramento pest calendar lays out the year month by month, and the technician will tell you honestly if a visit is better held until conditions improve.
Can I fill the burrows myself?
Filling burrows before the animals are gone mostly makes them dig a new entrance, and it can hide how active the system is. A technician confirms which burrows are empty, then fills them so the ground is level. Only fill a burrow yourself if the technician has confirmed it is inactive.
Hose-flooding and homemade fixes rarely work on a long, deep burrow system, and in clay-heavy valley soil water can soften the ground around slabs and fences.
Leave levee and canal burrows to the agency that maintains them.
