Lethe europa
In 3 days ~20% in a week ~40%
Lethe europa, otherwise known as the bamboo treebrown, is a species of Satyrinae butterfly found in Asia. The inner third of the hindwing is covered with long brown hairs. The upper side is a rich dark brown, with the forewing showing through a short oblique white discal fascia from the underside. This is accompanied by two obscure black ocelli, followed by two prominent white spots, the upper of which is double. Black markings occur along the terminal margins of both forewing and hindwing, outwardly bordered with pale dusky brown, with an obscure subterminal pale line on the hindwing.
The underside is a very dark blackish brown. Both wings are crossed sub-basally by a slender lilacine-white straight line, followed on the forewing by an oblique short white discla fascia. A postdiscal series of large black ocelli is present on both wings, with a terminal narrow ochraceous band bordered internally by a silvery-purple line. These ocelli are further bordered by inwardly and outwardly curving silvery-purple lunular lines; on the forewing these curve inward, while on the hindwing they curve outward. The forewing ocelli are confluent, black, and without pupils... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Kanha National Park | 🇮🇳 India | |
| 2 | Taroko National Park | 🇹🇼 Taiwan | |
| 3 | Kaeng Krachan National Park | 🇹🇭 Thailand |
With luck
About 10% of wildlife watchers report a Bamboo Treebrown sighting in Hong Kong on a given day, based on 50 verified sightings from GBIF citizen-science data. It is the 212th most-seen of the 1125 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
March to December
In those months about 10% of wildlife watchers report a Bamboo Treebrown in Hong Kong on a given day, against under 5% in January and February, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Bamboo Treebrown sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 12 cities where we can rate Bamboo Treebrown sightings, Hong Kong ranks 6th at about 10%, level with the leaders once rounded. The best odds are in Dehradun (India, about 10%), Bengaluru (India, about 10%) and Dhaka (Bangladesh, about 10%).
GBIF citizen-science records
It is estimated from how often the Bamboo Treebrown is recorded against all the insects logged in Hong Kong (50 verified sightings), 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.
