The federally endangered Taylor's checkerspot (Euphydryas editha taylori) is an increasingly rare prairie butterfly in the Willamette Valley-Puget Trough-Georgia Basin ecoregional complex. Since the arrival of European settlers, several factors have reduced available native host plants for E. e. taylori larvae. The most common host is now Plantago lanceolata, an exotic species long prevalent in the area. Local biologists have observed that the known native hosts have low available biomass relative to P. lanceolata, and may senesce too early to support the animals throughout their entire larval feeding cycle. Federally threatened Castilleja levisecta, which often grows larger and persists longer than currently-utilized native hosts, may have been important historically but its range does not now overlap with E. e. taylori. Previous work with other E. editha ssp. has shown that oviposition preference is: 1) heritable and may provide clues to which hosts were used historically, and 2) has been correlated with larval success so might indicate which hosts would be most effective for population restoration. We undertook an oviposition preference experiment to determine which potential hosts were preferred by E. e. taylori among P. lanceolata, C. levisecta, and the more common congener, C. hispida. The two Castilleja spp. were preferred equally, but C. levisecta was preferred over P. lanceolata. If further research confirms the suitability of C. levisecta as a host for E. e. taylori, restoration efforts for the two species could be united, and the effectiveness of both might be synergistically increased.