A baby or ground squirrel running in circles could be infected with rabies, poisoned, or suffered some inner ear damage.
If it loses balance then it could be a result of a fall or being drunk.
To see if it is rabies:
Put out a shallow dish of water. If the squirrel doesn’t drink and has foam in its mouth, it’s rabies. If not, it’s probably parasites.
Pro Tip: You can set-up a garden camera (CHECK ON AMAZON) to record if you can’t stay up all night.
If it’s under your home then you would be wise to call fish and game and have them test it. Certain parasites can be transferred to humans and are really nasty.
ALSO SEE: Do Squirrels Eat Mealworms?
Why is a Ground or Baby Squirrel Running in Circles? FIND OUT
It’s could be that it’s been hit by a car causing some sort of head injury and that’s why it’s behaving like this. I have seen this happen on the roads and sadly there isn’t much you can do.
Also, Squirrels that display this type of behavior, at least here in the Western U.S, often have maladies that feature serious aspects as far as contact with humans is concerned.
Squirrel with rabies symptoms is the worst possible cause, and that could be closely followed by West Nile virus.
There have been reports, recent ones, of squirrels and other mammals becoming infected with this mosquito borne virus.
Some squirrels are affected by inner ear problems that cause imbalance, but often goes away (just as in humans) after two or three weeks.
(Myxomatosis only affects rabbits, by the way)
ALSO SEE: How to Comfort a Dying Chipmunk
How to Care for a Baby Squirrel that fell out of Tree and now runs in Constant Circles
Walking or running in circles is a sign of neurological damage or head trauma, from the fall he had. Honestly, he might not be able to make it since this is hard to treat.
However, you could try seeing a vet. The doctor might be able to point you in the direction of the closest rehabber – or the Humane Society should know.
In the meantime, you should try keeping him warm by putting his box half on a heating pad (CHECK ON AMAZON) turned on “low”.
I recommend putting half the box on heating pad so that he can move away from the heat whenever he wants to.
Take out a towel and use an old tress shirt or a piece of fleece for his bedding – their toenails can get caught in the loops on towels. If he is old enough to run around, he may be hard to feed – put a few pieces of peeled apple in for him, and a few pecan halves. If you give him any formula, get Esbilac Puppy Replacement – do not use cow’s milk. Feed him VERY SLOWLY, and make sure the formula or water is warm, and that he is warm also. And be sure to get hold of a vet or the Humane Society first thing in the morning.