Papilio multicaudata
In 3 days ~40% in a week ~70%
Papilio multicaudata, the two-tailed swallowtail, is a species of the family Papilionidae found in western North America from British Columbia to Central America. The two-tailed swallowtail is a large swallowtail of western North America, one of several species that have yellow wings with black tiger striping. Each hindwing has several blue markings (top and bottom). Like other striped swallowtails, it has a small orange eyespot near the lower angle of each hindwing; the eyespots can fool predators into attacking the rear of the butterfly instead of the head, giving the butterfly a chance to escape. Its appearance is similar to the western, and eastern tiger swallowtails, but has narrower black stripes and usually two tails on each hindwing (rather than only one). Most two-tails have a black "slit pupil" in the orange eyespot on each hindwing, never present in western tiger. It is also usually larger than similar swallowtails within its range, although some eastern tiger swallowtails are as big as any two-tailed. The wingspan ranges from 3 to 6.5 inches (7.6 to 16.5 cm), making it the largest swallowtail in western North America. As is the case with most swallowtails... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Zion National Park | 🇺🇸 United States | |
| 2 | Guadalupe Mountains National Park | 🇺🇸 United States | |
| 3 | Grand Canyon National Park | 🇺🇸 United States | |
| 4 | Big Bend National Park | 🇺🇸 United States | |
| 5 | Grand Teton National Park | 🇺🇸 United States | |
| 6 | Rocky Mountain National Park | 🇺🇸 United States | |
| 7 | Saguaro National Park | 🇺🇸 United States | |
| 8 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Toluca | 🇲🇽 México | |
| 2 | Mexico City | 🇲🇽 México | |
| 3 | Puebla | 🇲🇽 México | |
| 4 | Ciudad Juárez | 🇲🇽 México | |
| 5 | San Luis Potosí | 🇲🇽 México | |
| 6 | Denver | 🇺🇸 United States | |
| 7 | León | 🇲🇽 México | |
| 8 | Salt Lake City | 🇺🇸 United States | |
| 9 | San Antonio | 🇺🇸 United States | |
| 10 | Austin | 🇺🇸 United States |
Possible
About 20% of wildlife watchers report a Two-Tailed Swallowtail sighting in Big Bend National Park on a given day, based on 40 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 45th most-seen of the 329 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
September
In that month about 40% of wildlife watchers report a Two-Tailed Swallowtail in Big Bend National Park on a given day, against under 5% in November to February, the lowest months. That is one of Big Bend National Park's wettest months, with about 50 mm of rain against 10 mm in April.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Two-Tailed Swallowtail sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 8
Of the 8 parks where we can rate Two-Tailed Swallowtail sightings, Big Bend National Park ranks 4th at about 20%. The best odds are in Zion National Park (United States, about 30%), Guadalupe Mountains National Park (United States, about 20%) and Grand Canyon National Park (United States, about 20%).
Same genus: Papilio
The closest relatives of the Two-Tailed Swallowtail that you can see in Big Bend National Park (genus Papilio, Common Swallowtails) are Black Swallowtail (about 10%) and Western Giant Swallowtail (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Two-Tailed Swallowtail is recorded against all the insects logged in Big Bend National Park (40 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
