Western Tiger Swallowtail
Papilio rutulus
Last reviewed: May 2026
Western Tiger Swallowtail is known for its bright yellow wings with bold black tiger stripes.
Host plants
Western Tiger Swallowtail caterpillars can only develop on their larval host plants. Plant one of these natives and you can host the full life cycle in your own yard (host plant associations per the Xerces Society (opens in new tab)).
- American Aspen (Populus tremuloides)
- Scouler's Willow (Salix scouleriana)
- Fraxinus latifolia — see Utah Ash (same genus)
- Red Willow (Salix laevigata)
Want Western Tiger Swallowtail in your yard? Open American Aspen in Pollinator Patch and plan an HOA-friendly garden around it for your region.
Family
Papilionidae
Wingspan
80–130 mm
Active
May through September
Range
WA, CO, ID, MT and 8 more states
How to identify it
Distinguish from other swallowtails by its large size, bright yellow base color with prominent black stripes, and distinctive tiger-like wing pattern.
Good to know
- Males often patrol territories near host plants to find mates
- Large, striking butterfly easily recognized by its yellow and black tiger striped pattern
Common questions
- What do Western Tiger Swallowtail caterpillars eat?
- Western Tiger Swallowtail caterpillars feed on Populus tremuloides, Salix scouleriana, Fraxinus latifolia, and Salix laevigata. These are the larval host plants the caterpillars must have to develop, per the Xerces Society and host plant records compiled from GBIF and iNaturalist.
- Where do Western Tiger Swallowtail live?
- Western Tiger Swallowtail is found across WA, CO, ID, MT and 8 more states.
- When are Western Tiger Swallowtail active?
- Adult Western Tiger Swallowtail are typically on the wing from May through September.
Range and life-history data compiled from iNaturalist, GBIF, and the Xerces Society. Photo licensed cc-by-nc-nd.