I live in Davis and have found two sprinkler heads eaten by a rodent down to the riser pipe. What kind of rodent is it? How can I prevent them from eating the sprinkler heads?
– Stan Naguwa, Davis
It’s important to identify your pest before taking action, according to UC master gardeners. Most likely, it’s a squirrel or vole.
Voles, also called meadow mice, are mouselike rodents somewhat similar in appearance to pocket gophers. Although voles spend considerable time above ground, most of their time is spent below ground in their burrow system.
The clearest signs of their presence are the well-traveled, above-ground runways that connect burrow openings; the runways are usually hidden beneath a protective layer of grass or other ground cover.
Voles are active day and night, year round. They’ll chew almost anything – including drip irrigation lines and sprinkler heads. They are normally found in areas with dense vegetation. To prevent vole damage, you need to manage the population in an area before it reaches high numbers. This often can be achieved by removing or reducing the vegetative cover.
Monitoring for their presence and modifying their habitat are essential. A wire fence at least 12 inches above the ground with a mesh size of one-quarter inch or less will help to exclude voles from entire gardens.
Trapping, baiting and repellents are also available. For extensive information on eradicating voles, go to www.ipm.ucdavis.edu and look for “Pest Note on Voles,” No. 7439. Or send a self-addressed, stamped business-size envelope to: Pest Notes, No. 7439, UC Cooperative Extension, 4145 Branch Center Drive, Sacramento, CA 95827.
A ground squirrel also may have chewed your sprinkler – particularly if you don’t see evidence of tunnels or runways. Although ground squirrels look similar to tree squirrels and can climb trees, when frightened they will retreat to a burrow, whereas tree squirrels will climb a tree or tall structure and not use a burrow.
Tree squirrels are distinguished from ground squirrels by their long bushy tails and lack of flecklike spots or stripes. Ground squirrels can create havoc by digging lots of holes.
There is no question that dealing with squirrels can be a real problem. Squirrels are known to chew on plastic sprinkler heads and irrigation lines and will chew on wood.
With pet rabbits, a block of wood in their cage gives them something to work their teeth against. Perhaps a few small pieces of 2-by-4 in your yard would cause the squirrels to leave the sprinklers alone.
Anything citrus – particularly lemon – helps keep squirrels away. So does cayenne pepper. Grannick’s Bitter Apple spray, available at PetSmart and other major chains, is a proven squirrel repellent and is safe for sprinklers and other things squirrels might chew, such as patio furniture and cushions.
If ground squirrels are a problem in your yard, additional information on their control can be found in the “Ground Squirrel Pest Note” at www.ipm.ucdavis.edu. For a copy of this pest note, please send a self-addressed, stamped business-size envelope requesting PN 7438 at the above address.