Seamless technique and golden tone are the hallmarks of mandolinist John Reischman, who returned to San Diego Saturday night, along with his captivating band The Jaybirds. As the crow flies, it’s about 1,132 miles from San Diego to British Columbia, where Reischman and most of the band are based. That sort of explains why they haven’t played here since 2006. But given the exquisite yet understated performance, their many fine recordings, and the wildly growing popularity of bluegrass and similar strains, I cannot understand why they did not fill the little church venue in Normal Heights.