Petrophora chlorosata
In 3 days ~20% in a week ~40%
Petrophora chlorosata, the brown silver-line, is a moth of the family Geometridae found in Asia and Europe. The larvae feed on bracken. It was first described by the Italian physician and naturalist, Giovanni Antonio Scopoli in his 1763 Entomologia Carniolica. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Biebrza National Park | 🇵🇱 Poland | |
| 3 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 4 | Cévennes National Park | 🇫🇷 France | |
| 5 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 6 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Porto | 🇵🇹 Portugal | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | London | 🇬🇧 United Kingdom | |
| 4 | Helsinki | 🇫🇮 Finland |
With luck
About 10% of wildlife watchers report a Brown Silver-Line sighting in Porto on a given day, based on 50 verified sightings from GBIF citizen-science data. It is the 134th most-seen of the 498 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.
April
In that month about 20% of wildlife watchers report a Brown Silver-Line in Porto on a given day, against under 5% in July to February, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Brown Silver-Line sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 4 cities where we can rate Brown Silver-Line sightings, Porto has the highest daily chance: about 10%. Next come Birmingham (United Kingdom, about 10%) and London (United Kingdom, under 5%).
Same order: Lepidoptera
The closest relatives of the Brown Silver-Line that you can see in Porto (order Lepidoptera, Butterflies and Moths) are Speckled Wood (about 30%), Red Admiral (about 20%) and Double-Striped Pug (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Brown Silver-Line is recorded against all the insects logged in Porto (50 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.
