Eurema smilax
In 3 days ~10% in a week ~20%
Eurema smilax, the small grass yellow, is a small pierid butterfly species found in Australia, with some additional records from India, Indonesia and Niger. The wingspan is about 30 mm. The larvae mostly feed on plants of the Senna and Neptunia genera.
The species was first described by Edward Donovan in 1805. Eurema smilax adults have a wingspan of 30–34 mm, with females being slightly larger than males. They are yellow, with black tips on the upper surface of the forewings. This colouration can vary depending on flight period. In southern Australia, the summer flying forms are usually pale yellow, with few or no brown markings on the wing undersides. The winter forms are a brighter yellow, with pronounced brown markings on the wing undersides. The males are generally a brighter yellow than the females.
The eggs are initially white, later turning yellowish. They are spindle-shaped, with a height of about 1.2 mm, and laid singly on a host plant. They hatch in about 7–11 days during spring. The caterpillar is initially pale yellow, soon becoming greenish. Third and fourth instars develop a darker dorsal line and a yellow lateral line. Mature larvae are... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Flinders Ranges National Park | 🇦🇺 Australia | |
| 2 | Uluru-Kata Tjuta National Park | 🇦🇺 Australia | |
| 3 | Lamington National Park | 🇦🇺 Australia | |
| 4 | Blue Mountains National Park | 🇦🇺 Australia |
Rare
Under 5% of wildlife watchers report a Small Grass-Yellow sighting in Blue Mountains National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 681st most-seen of the 789 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April–May, October and December
In those months about 10% of wildlife watchers report a Small Grass-Yellow in Blue Mountains National Park on a given day, against under 5% in January–March, June–September and November, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Small Grass-Yellow sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 4
Of the 4 parks where we can rate Small Grass-Yellow sightings, Blue Mountains National Park ranks 4th at under 5%. The best odds are in Flinders Ranges National Park (Australia, about 30%), Uluru-Kata Tjuta National Park (Australia, about 10%) and Lamington National Park (Australia, about 10%).
Same family: Pieridae
The closest relatives of the Small Grass-Yellow that you can see in Blue Mountains National Park (family Pieridae, Whites, Yellows, and Sulphurs) are Small White (about 20%), Caper White (about 20%) and Black Jezebel (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Small Grass-Yellow is recorded against all the insects logged in Blue Mountains National Park (5 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.
