Chalastra aristarcha
In 3 days ~30% in a week ~50%
Chalastra aristarcha, the silver fern moth, is a moth of the family Geometridae. This species was first described by Edward Meyrick in 1892. It is endemic to New Zealand and is found in the North Island. This species inhabits dense native forest. The larvae feed on the species host plant, the Silver fern, during spring. This species then pupates on top of leaf litter or moss on the ground. The pupation state lasts for approximately 6 weeks. Adult moths are on the wing from October until April but can sometimes also be seen during the winter months. Adults can be disturbed from silver ferns during the day or are seen on the wing at night particularly at Metrosideros perforata when in flower. Adults are attracted to light. It has been hypothesised that the range of C. aristarcha has restricted as a result of urban development and land conversion of its habitat.
This species was first described by Edward Meyrick in 1892 using a specimen collected by George Hudson in Wellington and named Selidosema aristarcha. Hudson discussed and illustrated this species using that name both in his 1898 book New Zealand moths and butterflies (Macro-lepidoptera) and his 1928 book The butterflies... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Egmont National Park | 🇳🇿 New Zealand |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Auckland | 🇳🇿 New Zealand |
With luck
About 10% of wildlife watchers report a Silver Fern Looper sighting in Egmont National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 123rd most-seen of the 191 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.
March and October
In those months about 20% of wildlife watchers report a Silver Fern Looper in Egmont National Park on a given day, against under 5% in May–September and November–December, the lowest months.
Between 8 and 11 pm
Across all the parks we cover, that three-hour window holds the most Silver Fern Looper sightings with a recorded time, and nearly all of them come between 6 pm and 6 am: it is mostly seen at night.
Only Egmont National Park, in our data
Egmont National Park is the only park on Wallace's Line with enough records to rate Silver Fern Looper sightings: about 10% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Silver Fern Looper is recorded against all the insects logged in Egmont National Park (6 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.
