Eurema andersoni
In 3 days ~20% in a week ~40%
Eurema andersonii, the one-spot grass yellow or Anderson's grass yellow, is a small butterfly of the family Pieridae, that is, the yellows and whites, which is found in Bangladesh, India, Myanmar and other parts of Asia.
Wet form: Male. Upper-side. Fore-wing with the outer marginal band moderately broad, the medial portion inclined slightly inward, and the lower portion very slightly inclined obliquely-outward. Hind-wing with a moderately broad outer band. Underside with slightly defined ordinary markings. Fore-wing with two cell-marks, basal obsolescent. Female not seen.
Dry form (fig. 2a, b). Male. Upper-side similar to the wet form. Underside with the ordinary markings distinct. Fore-wing with a medial cell mark, and a more or less well-defined sub-apical patch. Female. Upper-side paler. Fore-wing with slightly broader outer band. Hind-wing with a moderately broad outer band. Underside similar to the male. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cat Tien National Park | 🇻🇳 Vietnam | |
| 2 | Taroko National Park | 🇹🇼 Taiwan | |
| 3 | Kaeng Krachan National Park | 🇹🇭 Thailand |
With luck
About 10% of wildlife watchers report a One-Spot Grass Yellow sighting in Kaeng Krachan National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 194th most-seen of the 296 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–May and November–January
In those months about 10% of wildlife watchers report a One-Spot Grass Yellow in Kaeng Krachan National Park on a given day, against under 5% in February and June–October, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most One-Spot Grass Yellow 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 3 parks where we can rate One-Spot Grass Yellow sightings, Kaeng Krachan National Park ranks 3rd at about 10%, level with the leaders once rounded. The best odds are in Cat Tien National Park (Vietnam, about 10%) and Taroko National Park (Taiwan, about 10%).
Same family: Pieridae
The closest relatives of the One-Spot Grass Yellow that you can see in Kaeng Krachan National Park (family Pieridae, Whites, Yellows, and Sulphurs) are Yellow Orange Tip (about 30%), Orange Gull (about 20%) and Redspot Sawtooth (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the One-Spot Grass Yellow is recorded against all the insects logged in Kaeng Krachan 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.
