Thoas Swallowtail
Daily sighting probability ~30% · Possible
at Iguaçu National Park

In 3 days ~70% in a week ~90%

124 Verified sightings at Iguaçu National Park From 2019 to 2026
738 In all 28 parks
September Best month
☀️ Diurnal When it's spotted

About the Thoas Swallowtail

Papilio thoas, the king swallowtail or Thoas swallowtail, is a butterfly of the family Papilionidae. It is found in the southernmost United States, Mexico, Central America and South America (as far south as Argentina and Uruguay). The species is easily confused with the giant swallowtail, which it closely resembles in both larval and adult stages. The caterpillars feed on the leaves of citrus plants (Rutaceae). They have also been reported as feeding on a member of the genus Piper.

A large species (12 to 14 cm (4.7 to 5.5 in) wingspan. The wings are narrow. The forewings are mostly brown. A yellow band runs from the tip, becoming narrower towards the back. There is also a row of yellow arcuate spots on the underside of the wing edge. The hind wings are predominantly brown, toothed and have a long caudal process. This carries a yellow core. There is a row of yellow arcuate spots at the edge of the hind wings. A broad yellow band runs through the first half of the wing. Inside sits a black eyespot with blue-white dusting. The yellow regions are more pronounced on the undersides of the wings. Blue-white arcuate spots adjoin the yellow arcuate spots on the upper side... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Brownsberg Nature Park 🇸🇷 Suriname
~50%
2 Iguazú National Park 🇦🇷 Argentina
~40%
3 Iguaçu National Park 🇧🇷 Brazil
~30%
4 Bastimentos Island National Marine Park 🇵🇦 Panama
~30%
5 Soberanía National Park 🇵🇦 Panama
~20%
6 Pico Bonito National Park 🇭🇳 Honduras
~20%
7 Tortuguero National Park 🇨🇷 Costa Rica
~20%
8 Lago de Yojoa 🇭🇳 Honduras
~20%
9 Tambopata National Reserve 🇵🇪 Peru
~20%
10 Piedras Blancas National Park 🇨🇷 Costa Rica
~20%
11 Manuel Antonio National Park 🇨🇷 Costa Rica
~20%
12 Manu National Park 🇵🇪 Peru
~20%
13 Ostional Wildlife Refuge 🇨🇷 Costa Rica
~20%
14 Gandoca-Manzanillo Wildlife Refuge 🇨🇷 Costa Rica
~10%
15 Cerro Azul Meámbar National Park 🇭🇳 Honduras
~10%
16 Tenorio Volcano National Park 🇨🇷 Costa Rica
~10%
17 Braulio Carrillo National Park 🇨🇷 Costa Rica
~10%
18 La Amistad International Park (Panama) 🇵🇦 Panama
~10%
19 Parque Natural Metropolitano 🇵🇦 Panama
~10%
20 Corcovado National Park 🇨🇷 Costa Rica
~10%
21 Carara National Park 🇨🇷 Costa Rica
~10%
22 Monteverde Cloud Forest Reserve 🇨🇷 Costa Rica
~10%
23 Chirripó National Park 🇨🇷 Costa Rica
~10%
24 Yasuní National Park 🇪🇨 Ecuador
~10%
25 Cahuita National Park 🇨🇷 Costa Rica
~10%
26 Tijuca National Park 🇧🇷 Brazil
~10%
27 Arenal Volcano National Park 🇨🇷 Costa Rica
~10%
28 Tapantí-Macizo de la Muerte National Park 🇨🇷 Costa Rica
~10%

Cities Where Found

# City Country Daily sighting probability
1 São Luís 🇧🇷 Brazil
~50%
2 Santa Cruz de la Sierra 🇧🇴 Bolivia
~40%
3 Salvador 🇧🇷 Brazil
~30%
4 João Pessoa 🇧🇷 Brazil
~30%
5 Fortaleza 🇧🇷 Brazil
~30%
6 Mendoza 🇦🇷 Argentina
~30%
7 Recife 🇧🇷 Brazil
~20%
8 Valencia 🇻🇪 Venezuela
~20%
9 Manaus 🇧🇷 Brazil
~20%
10 Natal 🇧🇷 Brazil
~20%

Before you go

What are the chances of seeing a Thoas Swallowtail in Iguaçu National Park?

Possible

About 30% of wildlife watchers report a Thoas Swallowtail sighting in Iguaçu National Park on a given day, based on 124 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 15th most-seen of the 279 insects we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.

When is the best time to see a Thoas Swallowtail in Iguaçu National Park?

February and September

In those months about 50% of wildlife watchers report a Thoas Swallowtail in Iguaçu National Park on a given day, against under 5% in July, the lowest month.

What time of day is best to see a Thoas Swallowtail?

Between 10 am and 1 pm

Across all the parks we cover, that three-hour window holds the most Thoas Swallowtail sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.

Is Iguaçu National Park the best place to see a Thoas Swallowtail?

3rd of 28

Of the 28 parks where we can rate Thoas Swallowtail sightings, Iguaçu National Park ranks 3rd at about 30%. The best odds are in Brownsberg Nature Park (Suriname, about 50%) and Iguazú National Park (Argentina, about 40%). All parks ranked.

Which relatives of the Thoas Swallowtail live in Iguaçu National Park?

Same genus: Papilio

The closest relatives of the Thoas Swallowtail that you can see in Iguaçu National Park (genus Papilio, Common Swallowtails) are Astyalus Swallowtail (about 30%), Ruby-Spotted Swallowtail (about 20%) and Androgeus Swallowtail (about 10%), with each one's daily chance of a sighting.

Where does the Thoas Swallowtail sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Thoas Swallowtail is recorded against all the insects logged in Iguaçu National Park (124 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.

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