Pachycnemia hippocastanaria
In 3 days ~10% in a week ~30%
Pachycnemia hippocastanaria, the horse chestnut moth, is a moth of the family Geometridae. It is found in most of Europe. The wingspan is 28–32 mm. Adults are on wing from April to May, and again in a partial second generation in August, usually with fewer and smaller moths. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cévennes National Park | 🇫🇷 France | |
| 2 | Wadden Sea National Park | 🇩🇪 Germany | |
| 3 | Sierra de Guadarrama National Park | 🇪🇸 Spain | |
| 4 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Porto | 🇵🇹 Portugal |
Rare
Under 5% of wildlife watchers report a Horse Chestnut Moth sighting in Sierra de Guadarrama National Park on a given day, based on 8 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 388th most-seen of the 597 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
April, July and September
In those months about 10% of wildlife watchers report a Horse Chestnut Moth in Sierra de Guadarrama National Park on a given day, against under 5% in May–June, August and October–March, the lowest months.
Between 11 pm and 2 am
Across all the parks we cover, that three-hour window holds the most Horse Chestnut Moth 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 Horse Chestnut Moth sightings, Sierra de Guadarrama National Park ranks 3rd at under 5%. The best odds are in Cévennes National Park (France, about 10%) and Wadden Sea National Park (Germany, about 10%).
Same family: Geometridae
The closest relatives of the Horse Chestnut Moth that you can see in Sierra de Guadarrama National Park (family Geometridae, Geometer Moths) are Yellow Shell Moth (about 10%), Heliothea discoidaria (about 10%) and Chimney-Sweeper (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Horse Chestnut Moth is recorded against all the insects logged in Sierra de Guadarrama National Park (8 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.
