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Western Tiger Swallowtail - Papilio rutulus

Western Tiger Swallowtail
Western Tiger Swallowtail - Papilio rutulus


It is a large swallowtail butterfly with black stripes on yellow wings giving it the tiger-like pattern. The wingspan is from 2 3/4 to 4 inches. It has blue and orange spots near the tail. Females are larger than males. It is found all across Western North America. It is one of the most common large butterflies you are likely to see in the Bay area, even in urban areas. Like many butterflies, it likes to drink from mud - for minerals as well as water.

Caterpillars (larva) are green, with inflatable orange-yellow and blue eyespots on its head, and sometimes tiny blue spots elsewhere. It takes 10-15 days for the caterpillar to change into a butterfly. Larva are high up in trees and are rarely seen. They have 2-3 broods - late February to November but are seen less after mid-August.

Two other species, the Anise Swallowtail and the Two-tailed Swallowtail look similar but can be distinguished with field marks described in good butterfly field guides.

For more information about butterflies see the Butterflies section and for other insects see the Insects section.


Nectar Plants

In the wild - California buckeye, yerba santas, brodiaeas, vetches, milkweed, dogbanes, thistles

In the garden - butterfly bush (Buddleia), zinnia

Host Plants for Caterpillars

Sycamore, ash, cottonwood, willow

Articles/Links about Western Tiger Swallowtails

  • Detailed species page from Butterflies and Moths of North America website. 
  • Photo of the caterpillar showing the spectacular eye-spots. 
  • Notes with status around Suisun Marsh as part of a long-term study of butterflies in Central California by Art Shapiro. 
  • Butterflies' S.F. habitat threatened, SFGate, 20 Oct 2012. The Western Tiger Swallowtail has adopted Market Street as if it were native habitat, patrolling the wide lanes for mates and laying eggs in the trees that line the street. 
  • Mural showing the story of the Western Tiger Swallowtail butterfly and the London Plane tree, two indigenous species found on Market Street, by Amber Hasselbring. 
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