Idaea trigeminata
In 3 days ~20% in a week ~40%
Idaea trigeminata, the treble brown spot, is a moth of the family Geometridae. It is found in Europe. The species has a wingspan of 23–25 mm. It is similar to Idaea dimidiata, but generally rather larger and somewhat paler; the front edge of the fore wings is marked with blackish or dark purplish grey, and there is a band of the same colour on the outer marginal area; the inner edge of this band is formed by the second line, and the outer edge is wavy, interrupted above the middle, and sometimes below also.The rough and rather flattened caterpillar tapers towards the head; in colour it is dusky brown. The markings comprise interrupted black lines and V-shaped blackish marks on the back. Buckler states that this caterpillar may be distinguished from those of its nearest allies by having a rather long, dingy ochreous bristle from each of the raised dots; these bristles, which are of the same thickness throughout, curve forwards on all rings to the ninth, and on the other three backwards. 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 | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Paris | 🇫🇷 France | |
| 4 | Vienna | 🇦🇹 Austria |
With luck
About 10% of wildlife watchers report a Treble Brown-Spot sighting in Cévennes National Park on a given day, based on 15 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 493rd most-seen of the 996 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
June
In that month about 20% of wildlife watchers report a Treble Brown-Spot in Cévennes National Park on a given day, against under 5% in July to April, the lowest months.
Between 10 pm and 1 am
Across all the parks we cover, that three-hour window holds the most Treble Brown-Spot sightings with a recorded time, and about half of them come between 6 pm and 6 am: it is seen both by day and at night.
Only Cévennes National Park, in our data
Cévennes National Park is the only park on Wallace's Line with enough records to rate Treble Brown-Spot sightings: about 10% of wildlife watchers there report one on a given day.
Same genus: Idaea
The closest relatives of the Treble Brown-Spot that you can see in Cévennes National Park (genus Idaea) are Portland Ribbon Wave (about 10%), Satin Wave (about 10%) and Idaea ostrinaria (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Treble Brown-Spot is recorded against all the insects logged in Cévennes National Park (15 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.
