The Western Tiger Swallowtail (Papilio rutulus)
The Western Tiger Swallowtail (Papilio rutulus) is a large distinctive butterfly, not to be mistaken for a Monarch, its wings have black strips on a yellow background. Swallowtails are named for their ‘tails’ on their hindwings that resemble tail feathers of swallows, and Papilio is Latin for the word meaning “butterfly.”
Identification: Large wingspan of 7cm – 10cm. Its wings have distinctive black coloured strips on a yellow background, with markings on the underside of the hindwing being all yellow and the forewing forming marginal bands.
Life Cycle: One flight annually. Males typically patrol canyons and hilltops in close proximity to water pools near rivers and streams waiting for receptive females to mate. Females will lay green shiny eggs on the underside of leaves on host plants where the larvae (caterpillars) will emerge to feed on the leaves. They will then become brown coloured chrysalides that look wood-like slung on branches and tree trunks, and hibernate over-winter. Depending on the weather, they will emerge as butterflies from between February (California) to May, June, or July in more northerly ranges. The life span as a butterfly is only 6 – 14 days.
Range: Found throughout western North America, west of the Rockies, from southern California to southern British Columbia and Alberta.
Habitats: Commonly seen around along riprarian corridors near rivers, lakes and streams, the Swallowtail will frequent woodland gardens, parks, canyons, and roadside meadows.
Food:
- Larvae (caterpillars) eat the leaves of cottonwood trees, aspen (Populus), willows (Salix), wild cherry (Prunus), and ash (Fraxinus).
- Adult (butterflies) eat the nectar of many flowering plants such as thistles, butterfly bush, sages, lavender, anise, catmint, and many others.
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