Horisme tersata
In 3 days ~10% in a week ~20%
Horisme tersata, commonly known as the fern moth or simply the fern, is a moth of the family Geometridae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775 and it can be found in the Palearctic realm.
The wingspan is 31–36 mm. The length of the forewings is 14–18 mm. The moths fly in one or two generations from May to August.[1] The larvae feed on Clematis vitalba. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cévennes National Park | 🇫🇷 France |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | London | 🇬🇧 United Kingdom |
Rare
Under 5% of wildlife watchers report a Fern Moth sighting in London on a given day, based on 11 verified sightings from GBIF citizen-science data. It is the 1005th most-seen of the 1504 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.
July
In that month about 10% of wildlife watchers report a Fern Moth in London on a given day, against under 5% in August to June, the lowest months.
Between 6 and 9 am
Across all the parks we cover, that three-hour window holds the most Fern Moth sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only London, in our data
London is the only city on Wallace's Line with enough records to rate Fern Moth sightings: under 5% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Fern Moth is recorded against all the insects logged in London (11 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.
