Western tiger swallowtail vs Anise swallowtail
These two are easy to mix up. Here's how to tell a western tiger swallowtail from an anise swallowtail, and whether either one bites or stings.
Western tiger swallowtail
Papilio rutulus
Anise swallowtail
Papilio zelicaon
≠The key differences
Western tiger swallowtail is larger and has bold black vertical tiger stripes across yellow wings; the anise swallowtail lacks these stripes and has a broad yellow band and black wing bases.
⚖︎Side by side
| Western tiger swallowtail | Anise swallowtail | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | Wingspan 70-100 mm | 65-80 mm wingspan |
| Colours | Yellow, Black, Blue, Green | Yellow, Black, Blue (hindwing scaling), Orange (submarginal spot) |
| Family | Papilionidae | Papilionidae |
| Habitat | Riparian woodlands, riverbanks, parks, gardens and suburban areas near host trees | Open habitats: gardens, fields, roadsides, meadows and open woodland edges; often near host plants in the carrot family. |
| Range | Western North America: from British Columbia and Alberta south through Washington, Oregon, California and into Baja California; eastward to the Rocky Mountains in places | Western North America: from British Columbia and Washington through California and into Baja California, and inland to parts of the Rocky Mountain region. |
| Active | Spring through early autumn; most active during warm daylight hours | Spring through autumn (multiple broods in warmer areas); active in daylight, most commonly mid-morning to afternoon. |
| Pest? | No | No |
🔍How to spot a western tiger swallowtail
- Large yellow butterfly with bold black 'tiger' stripes on forewings and hindwings
- Blue scaling band on the hindwing and one or more orange eyespots near the tail
- Distinctive swallowtail 'tails' on the hindwings
- Caterpillars: early instars resemble bird droppings; later instars green with prominent eye spots
🔍How to spot an anise swallowtail
- Mostly yellow wings with black bands along the wing bases and margins, not tiger-striped.
- Hindwings with a single tail, blue spots in the black margin and an orange eyespot with a black center near the inner edge.
- Wingspan 65-80 mm; older caterpillars green with black bands and orange spots, and an orange osmeterium when disturbed.
?Frequently asked questions
What is the difference between a western tiger swallowtail and an anise swallowtail?
Western tiger swallowtail is larger and has bold black vertical tiger stripes across yellow wings; the anise swallowtail lacks these stripes and has a broad yellow band and black wing bases.
Is a western tiger swallowtail or an anise swallowtail more dangerous?
Western tiger swallowtail: Non-toxic. Anise swallowtail: Non-toxic. Adults and caterpillars are not poisonous or dangerous to people. Harmless to people.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.