Sciurus carolinensis
The classic bounding pattern: big hind feet landing ahead of small front feet.
Hind 2–2.5 in, front ~1 in. Four front toes, five hind toes. Hind prints land ahead of the front pair. Groups of four prints with gaps between. Trail runs tree to tree.
Hardwood forest, parks, suburbs. Eastern North America, introduced widely elsewhere.
Diurnal
Nuts, seeds, buds, fungi
Squirrels fake-bury nuts when they think they're being watched.
Should I be concerned?
Harmless. Don't hand-feed.