Papilio helenus
In 3 days ~40% in a week ~70%
Papilio helenus, the red Helen, is a large swallowtail butterfly found in forests of southern India and parts of southeast Asia. Papilio helenus is rarely found in Sri Lanka, southern and north-east India, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Laos, Kampuchea, Vietnam, southern China (including Hainan, Guangdong province), Taiwan, southern Japan, South Korea, Ryukyu Islands, peninsular and eastern Malaysia, Brunei, Philippines, and Indonesia (Sumatra, Java, Bangka, Kalimantan, the Lesser Sunda Islands except Tanimbar).
In India it occurs along the Western Ghats from Kerala to Gujarat, also Palnis and Shevaroys, in the north from Mussoorie eastwards, to north-east India and onto Myanmar. Male. Upper-side rich brownish-black; cilia alternated with white. Fore-wing with slender longitudinal streaks of golden-yellow scales within the cell, and hairy-scaled broad streaks between the outer veins; lower base of the wing also sparsely speckled with golden-yellow scales. Hind-wing with a cream- white upper discal patch composed of three portions, a short almost quadrate portion in the costal interspace, and two lower large elongate portions in the subcostal... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cuc Phuong National Park | 🇻🇳 Vietnam | |
| 2 | Namdapha National Park | 🇮🇳 India | |
| 3 | Sinharaja Forest Reserve | 🇱🇰 Sri Lanka | |
| 4 | Periyar National Park | 🇮🇳 India | |
| 5 | Kaeng Krachan National Park | 🇹🇭 Thailand | |
| 6 | Khao Yai National Park | 🇹🇭 Thailand | |
| 7 | Cat Tien National Park | 🇻🇳 Vietnam | |
| 8 | Taroko National Park | 🇹🇼 Taiwan |
With luck
About 10% of wildlife watchers report a Red Helen Swallowtail sighting in Cat Tien National Park on a given day, based on 8 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 78th most-seen of the 125 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.
April to August
In those months about 20% of wildlife watchers report a Red Helen Swallowtail in Cat Tien National Park on a given day, against under 5% in September to March, the lowest months. Those are among Cat Tien National Park's wettest months, with about 330 mm of rain a month against 15 mm in February.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Red Helen 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.
7th of 8
Of the 8 parks where we can rate Red Helen Swallowtail sightings, Cat Tien National Park ranks 7th at about 10%. The best odds are in Cuc Phuong National Park (Vietnam, about 40%), Namdapha National Park (India, about 40%) and Sinharaja Forest Reserve (Sri Lanka, about 30%). All parks ranked.
Same genus: Papilio
The closest relatives of the Red Helen Swallowtail that you can see in Cat Tien National Park (genus Papilio, Common Swallowtails) are Great Mormon Swallowtail (about 20%), Lime Swallowtail (about 20%) and Common Mormon Swallowtail (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Red Helen Swallowtail is recorded against all the insects logged in Cat Tien National Park (8 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.
