Lysandra coridon
In 3 days ~10% in a week ~20%
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 |
Rare
Under 5% of wildlife watchers report a Chalkhill Blue sighting in Vienna on a given day, based on 30 verified sightings from GBIF citizen-science data. It is the 505th most-seen of the 1406 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
August and September
In those months about 10% of wildlife watchers report a Chalkhill Blue in Vienna on a given day, against under 5% in October to July, 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.
4th of 5
Of the 5 cities where we can rate Chalkhill Blue sightings, Vienna ranks 4th at under 5%. The best odds are in Prague (Czechia, about 10%), Budapest (Hungary, about 10%) and Warsaw (Poland, under 5%).
GBIF citizen-science records
It is estimated from how often the Chalkhill Blue is recorded against all the insects logged in Vienna (30 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.
