If the members of old-time/bluegrass quartet Hawktail look familiar, it’s because they play with the likes of Punch Brothers, Crooked Still, David Rawlings Machine, and Mike Marshall. As Hawktail, the young quartet leaves space in tunes old and new for modern exploration, like rich bass solos from Paul Kowert or darting fiddle navigation from Brittany Haas. In fact, she dazzles during this performance of “El Camino Pt. 2,” recorded for Paste. As the tune darts, she slashes into and races out of the rhythm, bright melodies twisting and turning. We added them to Big Ears 2019 last week after months of trying to make it happen, and we’re delighted to have ’em in Knoxville.