Petrophora chlorosata
In 3 days ~10% in a week ~20%
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 |
Rare
Under 5% of wildlife watchers report a Brown Silver-Line sighting in Helsinki on a given day, based on 8 verified sightings from GBIF citizen-science data. It is the 553rd most-seen of the 838 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.
May and June
In those months about 10% of wildlife watchers report a Brown Silver-Line in Helsinki on a given day, against under 5% in July to April, 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.
4th of 4
Of the 4 cities where we can rate Brown Silver-Line sightings, Helsinki ranks 4th at under 5%. The best odds are in Porto (Portugal, about 10%), Birmingham (United Kingdom, about 10%) and London (United Kingdom, under 5%).
GBIF citizen-science records
It is estimated from how often the Brown Silver-Line is recorded against all the insects logged in Helsinki (8 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.
