Perizoma alchemillata
In 3 days ~20% in a week ~30%
Perizoma alchemillata, the small rivulet, is a moth of the genus Perizoma in the family Geometridae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 2 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 3 | Wadden Sea National Park | 🇩🇪 Germany | |
| 4 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Helsinki | 🇫🇮 Finland | |
| 4 | Moscow | 🇷🇺 Russia |
With luck
About 10% of wildlife watchers report a Small Rivulet sighting in Cairngorms National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 260th most-seen of the 300 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
July
In that month about 10% of wildlife watchers report a Small Rivulet in Cairngorms National Park on a given day, against under 5% in August to June, the lowest months.
Between 10 pm and 1 am
Across all the parks we cover, that three-hour window holds the most Small Rivulet sightings with a recorded time, and about 7 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.
Among the best
Of the 4 parks where we can rate Small Rivulet sightings, Cairngorms National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Bavarian Forest National Park (Germany, about 10%).
GBIF citizen-science records
It is estimated from how often the Small Rivulet is recorded against all the insects logged in Cairngorms National Park (5 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.
