Perizoma alchemillata
In 3 days ~10% in a week ~20%
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 |
Rare
Under 5% of wildlife watchers report a Small Rivulet sighting in Wadden Sea National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 536th most-seen of the 818 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 and August
In those months about 10% of wildlife watchers report a Small Rivulet in Wadden Sea National Park on a given day, against under 5% in September 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.
3rd of 4
Of the 4 parks where we can rate Small Rivulet sightings, Wadden Sea National Park ranks 3rd at under 5%. The best odds are in Bavarian Forest National Park (Germany, about 10%) and Cairngorms National Park (United Kingdom, about 10%).
GBIF citizen-science records
It is estimated from how often the Small Rivulet is recorded against all the insects logged in Wadden Sea National Park (9 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.
