Lysandra coridon
In 3 days ~70% in a week >90%
The chalkhill blue (Lysandra coridon) is a butterfly in the family Lycaenidae. It is a small butterfly that can be found throughout the Palearctic realm, where it occurs primarily in grasslands rich in chalk. Males have a pale blue colour, while females are brown. Both have chequered fringes around their wings.
As with many blue butterflies, separation from similar species in the field is on the underside markings... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Triglav National Park | 🇸🇮 Slovenia | |
| 2 | Vanoise National Park | 🇫🇷 France | |
| 3 | Aigüestortes National Park | 🇪🇸 Spain | |
| 4 | Mercantour National Park | 🇫🇷 France | |
| 5 | Picos de Europa National Park | 🇪🇸 Spain | |
| 6 | Ordesa y Monte Perdido National Park | 🇪🇸 Spain | |
| 7 | Ecrins National Park | 🇫🇷 France | |
| 8 | Pyrénées National Park | 🇫🇷 France | |
| 9 | Hohe Tauern National Park | 🇦🇹 Austria | |
| 10 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 11 | Cévennes National Park | 🇫🇷 France |
Likely
About 40% of wildlife watchers report a Chalkhill Blue sighting in Aigüestortes National Park on a given day, based on 49 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 23rd most-seen of the 256 insects we can rate there. Over three days the chance rises to about 70%, and over a week to over 90%, if each day is a fresh chance.
August and September
In those months about 50% of wildlife watchers report a Chalkhill Blue in Aigüestortes National Park on a given day, against under 5% in March–June and October, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Chalkhill 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.
Among the best
Of the 11 parks where we can rate Chalkhill Blue sightings, Aigüestortes National Park ranks 3rd at about 40%, level with the leaders once rounded. The best odds are in Triglav National Park (Slovenia, about 40%) and Vanoise National Park (France, about 40%).
GBIF citizen-science records
It is estimated from how often the Chalkhill Blue is recorded against all the insects logged in Aigüestortes National Park (49 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.
