Northern Blue

Northern Blue

Lycaeides idas

Daily sighting probability ~30% · Possible
at Mercantour National Park

In 3 days ~70% in a week ~90%

54 Verified sightings at Mercantour National Park From 2019 to 2026
480 In all 13 parks
July Best month
☀️ Diurnal When it's spotted

About the Northern Blue

Plebejus idas, the Idas blue or northern blue, is a butterfly of the family Lycaenidae. It belongs to the subfamily of Polyommatinae. This butterfly is very rare with low population densities. This mainly due to human disturbance effecting and creating changes in vegetation. According to the Nature Conservancy, it is critically endangered. It is ranked as Ti, critically imperiled (Zverev, 2021).

In the summer of 2014, a fire in Vastmanland in South Central Sweden affected an area of 13,100 ha. After the fire the Idas Blues along with other species increased in numbers. This is presumed to be because of an increase in larval host plant abundance.

This species can be found in most of Europe (except parts of Spain... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Kluane National Park 🇨🇦 Canada
~40%
2 Vanoise National Park 🇫🇷 France
~30%
3 Mercantour National Park 🇫🇷 France
~30%
4 Jasper National Park 🇨🇦 Canada
~20%
5 Banff National Park 🇨🇦 Canada
~20%
6 Sierra Nevada National Park 🇪🇸 Spain
~20%
7 Ecrins National Park 🇫🇷 France
~10%
8 Aigüestortes National Park 🇪🇸 Spain
~10%
9 Glacier National Park 🇺🇸 United States
~10%
10 Grand Teton National Park 🇺🇸 United States
~10%
11 Yellowstone National Park 🇺🇸 United States
~10%
12 Pyrénées National Park 🇫🇷 France
~10%
13 Wadden Sea National Park 🇩🇪 Germany
<5%

Cities Where Found

# City Country Daily sighting probability
1 Munich 🇩🇪 Germany
~20%

Before you go

What are the chances of seeing a Northern Blue in Mercantour National Park?

Possible

About 30% of wildlife watchers report a Northern Blue sighting in Mercantour National Park on a given day, based on 54 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 36th most-seen of the 412 insects we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.

When is the best time to see a Northern Blue in Mercantour National Park?

June and July

In those months about 40% of wildlife watchers report a Northern Blue in Mercantour National Park on a given day, against under 5% in January–May and September–November, the lowest months.

What time of day is best to see a Northern Blue?

Between 11 am and 2 pm

Across all the parks we cover, that three-hour window holds the most Northern 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.

Is Mercantour National Park the best place to see a Northern Blue?

3rd of 13

Of the 13 parks where we can rate Northern Blue sightings, Mercantour National Park ranks 3rd at about 30%. The best odds are in Kluane National Park (Canada, about 40%) and Vanoise National Park (France, about 30%). All parks ranked.

Which relatives of the Northern Blue live in Mercantour National Park?

Same family: Lycaenidae

The closest relatives of the Northern Blue that you can see in Mercantour National Park (family Lycaenidae, Gossamer-winged Butterflies) are Scarce Copper (about 50%), Sooty Copper (about 40%) and Chalkhill Blue (about 40%), with each one's daily chance of a sighting.

Where does the Northern Blue sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Northern Blue is recorded against all the insects logged in Mercantour National Park (54 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.

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