Ask any nurseryman, gardener, crop grower etc. if they have ever had a problem with a varmint of a rodential nature and I’m sure you will get a headshake/sigh/groan… I have found out the hard way that you can have an arboretum, or you can have a colony of ground squirrels, but you must pick just one. The east side of the valley is absolutely plagued with the little darlings! These guys (and gals) will chew your beloved trees right down to the rocks faster than you can plant them!
If you try to just “live with them” let me know how you did it. I refuse to poison ANYTHING as I have been poisoned once myself, and it really is literal hell.
In addition to being a cruel way to die, the poison in the dead/dying animal is also just as deadly to the hapless predator or scavenger that comes upon the poisoned rodent.
One method of control would be introduction of predators. But remember ground squirrels are diurnal and are safe and sound in their burrow by sundown. Day hunting great horned owls, red tailed hawks and golden eagles will hammer them from above, and coyotes, foxes and bobcats will help with crepuscular hours of operation, so attracting these natural predators is a solid bet.
The wonder tool I have found for controlling ground squirrels is a #110 conibear or bodygrip trap. I have almost never seen one not work, when set properly. Ground squirrels use their own burrow entrance exclusively, and that is their downfall. Placed over the hole correctly will simply not allow access or egress with less than quickly fatal results. Remember, we don’t want them to suffer; we just want them to croak in the fastest way possible! (Believe me, I wish they would just leave my trees alone, but that would require a full-blown metal mesh prison around every planting). You will need to exclude EVERY non-target animal from these traps, as they are not choosy about snapping shut on anything that triggers them to go off. A wire cage that has no more than a 2” opening covering your set will work just dandy. Make positive that your set is on a squirrel hole only and you are home free. Local farm supply stores have them in stock, and with reasonable care, will last years.
Use care when handling any ground dwelling rodent, as fleabites are no fun, and can be a serious health risk. Use full-length gardening or dishwashing rubber gloves, and handle them as little as possible.
I have found that you need to eliminate about 80% of the colony to be able to manage the remaining 20% throughout the year. If you wait until late spring and early summer to knock the numbers down you will a very busy bee, so start setting traps around the first of February unless the snow precludes this. If you skip a season, the numbers will rebound to carrying capacity, and you will have to start all over from square one again.
While trapping may not appeal to many, if there was another way to manage ground squirrels I would do it in a heartbeat. A word of caution, if you accidentally stick your hand in a loaded trap, you will only do it once, trust me.
Some people live trap them, but give up eventually as sheer numbers of a colony makes it impossible to keep on top of exporting the captors, and moving live animals for relocation is a logistical nightmare when you try. Another note of caution, don’t try to use a regular rat trap, it just doesn’t have the horsepower needed for a humane (if there is one) kill. Good luck, and enjoy your trees this summer!