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 London on a given day, based on 8 verified sightings from GBIF citizen-science data. It is the 1300th most-seen of the 1504 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.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Chalkhill Blue in London on a given day, so our monthly data shows no clear season.
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.
5th of 5
Of the 5 cities where we can rate Chalkhill Blue sightings, London ranks 5th at under 5%. The best odds are in Prague (Czechia, about 10%), Budapest (Hungary, about 10%) and Warsaw (Poland, under 5%).
Same family: Lycaenidae
The closest relatives of the Chalkhill Blue that you can see in London (family Lycaenidae, Gossamer-winged Butterflies) are Holly Blue (about 30%), Small Copper (about 20%) and Common Blue (about 20%), 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 London (8 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.
