Byasa polyeuctes
In 3 days ~30% in a week ~50%
Byasa polyeuctes, the common windmill, is the most common member in India of the windmills genus (Byasa), comprising tailed black swallowtail butterflies with white spots and red submarginal crescents. This butterfly lives in Pakistan, northern ranges of India, Nepal, Bhutan, Myanmar, northern Thailand, Laos, Vietnam, southern China (including Yunnan) and Taiwan.
In India, the Himalayas from Himachal Pradesh to Sikkim, Assam onto Chinese South Tibet region and northern Myanmar. Overall, the butterfly is not rare. It is common in parts of Sikkim but becomes rarer westwards. It is extremely scarce in Shimla though not rare from Kangra.
In the west it ranges from the Azad Kashmir disputed territory part of the wider Kashmir region of Pakistan and India. Length 110 to 140 mm Sexes alike Black and white above with prominent swallowtail Red bodied - tail has a red tip
Forewings completely black above and below Hindwings crenulated deeply twice on each side of swallowtail. Large oblong white discal spot in 5 (both upperside and underside) and sometimes in 4. Upperside hindwing has irregular marginal red crescents in 1a, 2 and 3 and a small white... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Taroko National Park | 🇹🇼 Taiwan | |
| 2 | Doi Inthanon National Park | 🇹🇭 Thailand |
With luck
About 10% of wildlife watchers report a Common Windmill sighting in Doi Inthanon National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 105th most-seen of the 153 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
January and August
In those months about 20% of wildlife watchers report a Common Windmill in Doi Inthanon National Park on a given day, against under 5% in April–May, July and September–December, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Common Windmill sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Common Windmill sightings, Doi Inthanon National Park ranks 2nd at about 10%. The best odds are in Taroko National Park (Taiwan, about 30%).
Same family: Papilionidae
The closest relatives of the Common Windmill that you can see in Doi Inthanon National Park (family Papilionidae, Swallowtails and Parnassians) are Lime Swallowtail (about 10%), Paris Peacock Swallowtail (about 10%) and White Dragontail Butterfly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Common Windmill is recorded against all the insects logged in Doi Inthanon National Park (7 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.
