Generally uncommon in our area, largely confined to riparian corridors where it is greatly outnumbered by the Western Tiger Swallowtail. Generally rare to absent on the floor of the Central Valley. (Why?) Adults soar high in the trees, the males patrolling stream courses and roads. Two or three broods in the foothills; perhaps only one at Sierraville and at Verdi, NV, where quite common. Visits California Buckeye, Yerba Santa, Giant Hyssop, Milkweed, Lilies, and other large, showy flowers.