From the recording The Erin Trilogy

Erin ('77) (Prelude) (Trilogy 1 of 3)
Music by Gabriel Jarrod.
Performed by Charlie Burkett.
Mixed by Nikola Hamilton.
℗© 2021 Gabriel Jarrod/Drew Jarrod (BMI). All Rights Reserved.

(As good as anything Basil Poledouris did for Lonesome Dove.)