Cameraria ohridella
In 3 days ~20% in a week ~40%
The horse-chestnut leaf miner (Cameraria ohridella) is a leaf-mining moth of the family Gracillariidae. The horse-chestnut leaf miner was first observed in North Macedonia in 1984, and was described as a new species in 1986. Its larvae are leaf miners on the common horse-chestnut (Aesculus hippocastanum). The horse-chestnut leafminer was first collected and inadvertently pressed in herbarium sheets by the botanist Theodor von Heldreich in central Greece in 1879.
Cameraria ohridella causes significant damage, mainly late summer browning, to the appearance of horse-chestnut trees. Despite the poor appearance of these infested trees, there is no evidence that damage by the moth leads to tree death. Seed weight, photosynthetic storage and reproductive capacity may however be reduced. Trees survive repeated infestations and re-flush normally in the following year. It appears that most of the damage caused by the moth occurs too late in the growing season to greatly affect tree performance. Consequently, there is no reason to fell and remove trees just because they are attacked by C. ohridella.
The larva feeds in a mine in the leaves of the tree, damaging the leaves and stunting... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Triglav National Park | 🇸🇮 Slovenia | |
| 2 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 3 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | Kyiv | 🇺🇦 Ukraine | |
| 3 | Kharkiv | 🇺🇦 Ukraine | |
| 4 | London | 🇬🇧 United Kingdom | |
| 5 | Minsk | 🇧🇾 Belarus | |
| 6 | Sofia | 🇧🇬 Bulgaria | |
| 7 | Berlin | 🇩🇪 Germany | |
| 8 | Manchester | 🇬🇧 United Kingdom | |
| 9 | Warsaw | 🇵🇱 Poland | |
| 10 | Birmingham | 🇬🇧 United Kingdom |
With luck
About 10% of wildlife watchers report a Horse-Chestnut Leafminer sighting in Snowdonia National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 336th most-seen of the 387 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.
May and July–August
In those months about 10% of wildlife watchers report a Horse-Chestnut Leafminer in Snowdonia National Park on a given day, against under 5% in June and September–April, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Horse-Chestnut Leafminer sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 4 parks where we can rate Horse-Chestnut Leafminer sightings, Snowdonia National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Triglav National Park (Slovenia, about 10%).
Same order: Lepidoptera
The closest relatives of the Horse-Chestnut Leafminer that you can see in Snowdonia National Park (order Lepidoptera, Butterflies and Moths) are Drinker Moth (about 50%), Speckled Wood (about 40%) and Oak Eggar (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Horse-Chestnut Leafminer is recorded against all the insects logged in Snowdonia 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.
