Eastern tiger swallowtail vs Western tiger swallowtail
These two are easy to mix up. Here's how to tell an eastern tiger swallowtail from a western tiger swallowtail, and whether either one bites or stings.
Eastern tiger swallowtail
Papilio glaucus
Western tiger swallowtail
Papilio rutulus
≠The key differences
Eastern species with similar pattern; range does not overlap broadly in the west. Papilio glaucus females often show more extensive dark (melanic) form in some areas.
⚖︎Side by side
| Eastern tiger swallowtail | Western tiger swallowtail | |
|---|---|---|
| To humans | Non-toxic | Non-toxic |
| Size | 80-140 mm wingspan | Wingspan 70-100 mm |
| Colours | Yellow, Black, Blue (hindwing band), Orange (submarginal spot) | Yellow, Black, Blue, Green |
| Family | Papilionidae | Papilionidae |
| Habitat | Woodland edges, riversides, suburban gardens, fields and parks throughout eastern North America | Riparian woodlands, riverbanks, parks, gardens and suburban areas near host trees |
| Range | Eastern North America from Ontario and Maine south to Florida and west to the Great Plains; range overlaps with related tiger swallowtails in northern and western areas | Western North America: from British Columbia and Alberta south through Washington, Oregon, California and into Baja California; eastward to the Rocky Mountains in places |
| Active | Spring to early autumn (generally March-September; earlier in southern range); active by day, especially sunny periods | Spring through early autumn; most active during warm daylight hours |
| Pest? | No | No |
🔍How to spot an eastern tiger swallowtail
- Large yellow wings with bold black 'tiger' stripes across both fore- and hindwings
- Characteristic tail-like extensions on each hindwing
- Blue band and orange submarginal spots on the hindwing; females may be dark melanic form lacking yellow ground color
🔍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
?Frequently asked questions
What is the difference between an eastern tiger swallowtail and a western tiger swallowtail?
Eastern species with similar pattern; range does not overlap broadly in the west. Papilio glaucus females often show more extensive dark (melanic) form in some areas.
Is an eastern tiger swallowtail or a western tiger swallowtail more dangerous?
Eastern tiger swallowtail: Non-toxic. Western tiger swallowtail: Non-toxic. Not dangerous. Adults and caterpillars are not poisonous or dangerous 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.