You'll find them near where they live. This may not sound helpful, but when the woods are filled with nut trees, theyleavesigns to look for.
They build leaf nests which they abandon before they move into thetrees where you might spot some entrance holes. When there is snow on the ground, you'll see their tracks and small chips of tree bark by the bases of trees from them scampering up and down them over and over again.
You can hear them calling at certain times of the day, particularly the younger juvenile squirrels.
You'll see some empty or 1/2 eatenacorn shells scattered around, andshallowholes in fresh dirtwhere they have dugbelow the leavesof the forest floor.
There's topography too. They seem to prefer living within a short distance of a water source and alsoprefer areas that offer protection from storm winds which rock the trees, maybe in depressions and lower on hillsides. Water being presentusually produces more varietyand larger trees.
I think that they like larger, taller trees more than smaller ones, and extra large nut trees like a great oakare also a draw. Nut trees only produce for a short time, but squirrels also need food sources during the rest of the year.
Usually where there is one squirrel there are more nearby, but sometimes youcan't locatethem withoutscouting around until you find their sign.