Lysandra coridon
In 3 days ~30% in a week ~50%
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 |
With luck
About 10% of wildlife watchers report a Chalkhill Blue sighting in Prague on a given day, based on 207 verified sightings from GBIF citizen-science data. It is the 78th most-seen of the 724 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
August
In that month about 30% of wildlife watchers report a Chalkhill Blue in Prague on a given day, against under 5% in October to June, the lowest months. That is one of Prague's wettest months, with about 80 mm of rain against 30 mm in February.
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.
Yes
Of the 5 cities where we can rate Chalkhill Blue sightings, Prague has the highest daily chance: about 10%. Next come Budapest (Hungary, about 10%) and Warsaw (Poland, under 5%).
Same family: Lycaenidae
The closest relatives of the Chalkhill Blue that you can see in Prague (family Lycaenidae, Gossamer-winged Butterflies) are Common Blue (about 30%), Small Copper (about 10%) and Holly Blue (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Chalkhill Blue is recorded against all the insects logged in Prague (207 verified sightings), 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.
