In the unit from which I retired, the "Charge Mama" makes assignments, solves problems, keeps track of impending deliveries to which we will be invited, makes rounds for status updates, makes sure assignments in the 'back' nurseries are reasonable and appropriate. She helps out w/critical pts and admissions; if all three admit nurses are used up, she may have to take the next admit, or try to move babies around to free up other nurses. She assigns the "chores"--checking frig temps, meds, transport stuff, calibrationg bedside testing equipment--and makes sure they are accomplished.
She needs to have a lot of patience, good people skills, be able to prioritize in her sleep. She has to work w/medical staff, respiratory, ancillary personnel, and the 14-18 or so nurses, including registry and travelers on the shift.
She staffs for the oncoming shift. That may mean phone calls if we're short. Although there is a staffing office for the hospital, we cannot rely on them to do our staffing.
She sees any incident reports [QA's, whatever] first and writes her input before it goes to the nurse manager.
She does not take a pt. assignment unless there is absolutely NO choice.
I can't think of anything else, but I've probably left something imp't off this list.