This is a Sis baby, she (Sis) left a bit too soon. Because if this we were able to observe first hand how the female, blood relatives, will assist, and in some cases take over raising the young of the Matriarch.
While I didn't get this girl and that act she was face wiping big time. This is how squirrel mark 'squirrel highways' often leading right to a good food source..Bird feeders anyone??