Byasa polyeuctes
In 3 days ~70% in a week ~90%
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 |
Possible
About 30% of wildlife watchers report a Common Windmill sighting in Taroko National Park on a given day, based on 81 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 21st most-seen of the 447 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.
July to September
In those months about 40% of wildlife watchers report a Common Windmill in Taroko National Park on a given day, against about 10% in May, the lowest month.
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.
Yes
Of the 2 parks where we can rate Common Windmill sightings, Taroko National Park has the highest daily chance: about 30%. Next come Doi Inthanon National Park (Thailand, about 10%).
GBIF citizen-science records
It is estimated from how often the Common Windmill is recorded against all the insects logged in Taroko National Park (81 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.
