Flutes at night
The oldest account we could open was written by a Santee Dakota, one of the Sioux peoples alongside the Lakota. In Indian Boyhood (1902), Charles A. Eastman recalled his first years among the Sioux: young men played the carved flute late into the night for young women to hear, their robes pulled over their heads. The oldest Lakota flute we could check is a courting flute of 1918 by John R. Colhoff, born on the Pine Ridge Reservation to a Lakota mother. The Museum of Nebraska Art says he carved and painted it in the shape of a crane, a bird found in Sioux lore, and lists it as cedar with brass beads, cotton cord, hide and paint.
To verify: A Lakota courting flute of about 1870 with a calling elk carved into it, listed by The Metropolitan Museum of Art, which we could not open for this check