Maculinea arion
In 3 days ~20% in a week ~40%
The Large blue (Phengaris arion) is a species of butterfly in the family Lycaenidae. The species was first defined in 1758 and first recorded in Britain in 1795. In 1979 the species became mostly extinct in Britain but has been successfully reintroduced with new conservation methods. The species is classified as "near threatened" on the IUCN Red List of Threatened Species. Today P. arion can be found in Europe, the Caucasus, Armenia, western Siberia, Altai, north-western Kazakhstan and Sichuan.
The large blue can be distinguished by its unique speckled black dots on its wings with a blue background. The large blue butterfly is well known in behavioural ecology as it is a brood parasite of a single species of red ant, Myrmica sabuleti. The discovery was made by Captain Edward Bagwell Purefoy along with F. W. Frohawk and others.
Large blue caterpillars grow to about half an inch (13 millimetres... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Hohe Tauern National Park | 🇦🇹 Austria | |
| 2 | Aigüestortes National Park | 🇪🇸 Spain | |
| 3 | Vanoise National Park | 🇫🇷 France | |
| 4 | Mercantour National Park | 🇫🇷 France | |
| 5 | Ecrins National Park | 🇫🇷 France | |
| 6 | Pyrénées National Park | 🇫🇷 France | |
| 7 | Cévennes National Park | 🇫🇷 France |
With luck
About 10% of wildlife watchers report a Large Blue sighting in Cévennes National Park on a given day, based on 14 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 527th most-seen of the 996 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.
June and July
In those months about 10% of wildlife watchers report a Large Blue in Cévennes National Park on a given day, against under 5% in August to May, the lowest months. Those are among Cévennes National Park's driest months, with about 60 mm of rain a month against 260 mm in October.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Large Blue sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
7th of 7
Of the 7 parks where we can rate Large Blue sightings, Cévennes National Park ranks 7th at about 10%. The best odds are in Hohe Tauern National Park (Austria, about 20%), Aigüestortes National Park (Spain, about 10%) and Vanoise National Park (France, about 10%).
GBIF citizen-science records
It is estimated from how often the Large Blue is recorded against all the insects logged in Cévennes National Park (14 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.
