This is one of the very few butterflies adapted to climax Red Fir forest. It can be abundant at Donner and Castle Peak (below tree-line only), where males pack onto mud puddles along trails early in the season. Adults visit Aster, Pink Pussy-Paws, Coyotemint, etc. and remain in the sun, although surrounded by the fir canopy. There is considerable minor pattern variation.
The host plant was confirmed on Castle Peak in 2011 as Golden-Aster, Eucephalus (formerly Chrysopsis) breweri. A variety of Composites have been identified elsewhere, and woodland species of Aster are suspected.