Zigzag Fern Looper

Zigzag Fern Looper

Ischalis fortinata

Endemic
Daily sighting probability ~20% · Possible
at Rakiura National Park

In 3 days ~40% in a week ~70%

16 Verified sightings at Rakiura National Park From 2019 to 2026
31 In all 2 parks
November Best month
🌙 Nocturnal When it's spotted

About the Zigzag Fern Looper

Ischalis fortinata (also known as the zigzag fern looper) is a species of moth in the family Geometridae. It was first described by Achille Guenée in 1868. This species is endemic to New Zealand and has been observed in both the North, South and Stewart Islands. The species inhabits native forest. The larval hosts of this species include Polystichum vestitum and Polystrichum richardii. Adults have been observed all year around but are most frequently seen from October to February.

This species was first described by Achille Guenée in 1868 using a specimen collected by R. W. Fereday, in Canterbury, likely at Akaroa on the Banks Peninsula, and originally named the species Polygonia fortinata. In 1875 Cajetan von Felder & Alois Friedrich Rogenhofer, thinking they were describing a new species, tentatively named it as Caustaloma ziczac. This name was synonymised by Edward Meyrick in 1883. He placed the species in the genus Azelina. George Hudson discussed this species under this name in his 1928 book The butterflies and moths of New Zealand. In 1970 Robert W. Poole placed this species in the genus Ischalis. In 2004 this placement was confirmed. The male lectotype specimen... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Rakiura National Park 🇳🇿 New Zealand
~20%
2 Fiordland National Park 🇳🇿 New Zealand
~10%

Before you go

What are the chances of seeing a Zigzag Fern Looper in Rakiura National Park?

Possible

About 20% of wildlife watchers report a Zigzag Fern Looper sighting in Rakiura National Park on a given day, based on 16 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 30th most-seen of the 118 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.

When is the best time to see a Zigzag Fern Looper in Rakiura National Park?

November

In that month about 40% of wildlife watchers report a Zigzag Fern Looper in Rakiura National Park on a given day, against under 5% in January, March–April and June–September, the lowest months.

What time of day is best to see a Zigzag Fern Looper?

Between 9 pm and midnight

Across all the parks we cover, that three-hour window holds the most Zigzag Fern Looper sightings with a recorded time, and about 8 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.

Is Rakiura National Park the best place to see a Zigzag Fern Looper?

Yes

Of the 2 parks where we can rate Zigzag Fern Looper sightings, Rakiura National Park has the highest daily chance: about 20%. Next come Fiordland National Park (New Zealand, about 10%).

Where does the Zigzag Fern Looper sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Zigzag Fern Looper is recorded against all the insects logged in Rakiura National Park (16 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.

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