Chalastra aristarcha
In 3 days ~10% in a week ~20%
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 |
Rare
Under 5% of wildlife watchers report a Silver Fern Looper sighting in Auckland on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 618th most-seen of the 689 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.
December and January
In those months about 10% of wildlife watchers report a Silver Fern Looper in Auckland on a given day, against under 5% in February to November, 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 Auckland, in our data
Auckland is the only city on Wallace's Line with enough records to rate Silver Fern Looper sightings: under 5% of wildlife watchers there report one on a given day.
Same family: Geometridae
The closest relatives of the Silver Fern Looper that you can see in Auckland (family Geometridae, Geometer Moths) are Epyaxa lucidata (about 20%), Apple Looper (about 20%) and Cabbage Tree Moth (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Silver Fern Looper is recorded against all the insects logged in Auckland (5 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.
