If it's fall in Berrien, that means Ammodramid time. Usually we can find a LeConte's or two at Tiscornia, but hadn't yet encountered Nelson's there. Earlier in the month we flushed a short-tailed sparrow with the round wings of an Ammodramid, but that lacked the pale rump and bright back braces in flight that the LeConte's show. It also had more facial patterning than the blank face of a LeConte's in flight.
The bird would typically run away mouse-like and sometimes pause at the base of a tuft of dune grass. A lot of people want to look at the color of the crown stripe, but the gray nape is much easier to see in the field.