How do Plains Indian songs use descending melodic patterns?

In Plains Indian music, the use of descending melodic patterns is a defining stylistic feature. These songs are characterized by a cascading melodic contour that begins in a high register and descends by steps throughout the performance. This progression continues until the melody reaches its lowest pitch at the conclusion of the strophe.1

This structure is a primary element of the musical tradition practiced by various groups across the northern and southern Plains, such as the Blackfoot, Sioux, Kiowa, and Comanche.1