Check out this great video
Ground Squirrels are another burrowing rodent that we treat. Squirrels burrow in much the same way as voles because they do not seal the holes on their tunnels. Ground squirrels in lawns tend to tunnel in a straight line, leaving linear patches of yellow grass on the surface. What has happened when this occurs is that the squirrels have eaten the roots of the grass, killing it from beneath the surface and the pathway of their tunnel is visible by the discolored grass.
The open holes that ground squirrels are much larger than vole holes and the tunnel systems appear to be larger in diameter than gopher tunnels as well.
We treat ground squirrels with carbon monoxide as well as using lethal and live trapping. Ground squirrels are very susceptible to carbon monoxide, and using this method is very effective.
You will know if you have ground squirrels because of the large open holes. You will also see them on the surface. Ground squirrels tend to come out of their burrows to eat and sun themselves. They will stay on the surface until you get too close, and then they will scurry back underground. You will see their short tail standing up as they run. They are most active in the evenings and early mornings.