Cydia splendana
In 3 days ~20% in a week ~40%
Cydia splendana, the chestnut tortrix, is a moth of the family Tortricidae. It is found in Europe. It is also known as the acorn moth, but this can also refer to Blastobasis glandulella from North America, which belongs to the more primitive family Blastobasidae.
The wingspan is 12–16 mm. The moth flies from May to September depending on the location. The larvae feed on oak and sweet chestnut, and perhaps also Juglans species. The larvae develop mostly in mature chestnut fruits. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Wadden Sea National Park | 🇩🇪 Germany | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Cévennes National Park | 🇫🇷 France | |
| 4 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | London | 🇬🇧 United Kingdom | |
| 3 | Birmingham | 🇬🇧 United Kingdom | |
| 4 | Rotterdam [The Hague] | 🇳🇱 Netherlands | |
| 5 | Manchester | 🇬🇧 United Kingdom | |
| 6 | Berlin | 🇩🇪 Germany | |
| 7 | Essen | 🇩🇪 Germany | |
| 8 | Porto | 🇵🇹 Portugal | |
| 9 | Helsinki | 🇫🇮 Finland | |
| 10 | Paris | 🇫🇷 France |
With luck
About 10% of wildlife watchers report a Marbled Piercer sighting in Bavarian Forest National Park on a given day, based on 10 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 523rd most-seen of the 1115 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.
July and August
In those months about 10% of wildlife watchers report a Marbled Piercer in Bavarian Forest 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 Marbled Piercer sightings with a recorded time, and about 7 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.
Among the best
Of the 4 parks where we can rate Marbled Piercer sightings, Bavarian Forest National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Wadden Sea National Park (Germany, about 10%).
Same genus: Cydia
The closest relatives of the Marbled Piercer that you can see in Bavarian Forest National Park (genus Cydia) are Large Beech Piercer (about 10%) and Vagrant Piercer (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Marbled Piercer is recorded against all the insects logged in Bavarian Forest National Park (10 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.
