Agriades glandon
In 3 days ~30% in a week ~60%
Agriades glandon, the Arctic blue or Glandon blue, is a species of butterfly in the family Lycaenidae. It in found in Eurasia and North America. In North America, this species is found from Alaska east to Newfoundland, south through the mountains to Washington, northern Arizona, and northern New Mexico. In Europe, it is found in mountainous areas like the Pyrenees and Alps, as well as the far north. It is also found in parts of Russia, including Siberia, and Kamchatka. Its habitats include arctic tundra, subarctic and subalpine forests, mountain meadows, and bogs.
The wingspan is 17–26 mm. The male wing uppersides are silver-coloured, steely blue or pale shining blue and become increasingly brown towards the edges. The female wing uppersides are almost entirely brown but with a slightly bluish pollination in the basal region. The incidence of darkening increases with altitude. All wings usually have small, dark disk spots that are sometimes surrounded by white. Both sexes have white-rimmed black dots on the pale grey-brown ground of the forewing underside, while the underside of the hind wings reveals striking white spots and occasionally orange-colored... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Vanoise National Park | 🇫🇷 France | |
| 2 | Mercantour National Park | 🇫🇷 France | |
| 3 | Rocky Mountain National Park | 🇺🇸 United States | |
| 4 | Glacier National Park | 🇺🇸 United States | |
| 5 | Olympic National Park | 🇺🇸 United States | |
| 6 | Banff National Park | 🇨🇦 Canada | |
| 7 | Ecrins National Park | 🇫🇷 France | |
| 8 | Riding Mountain National Park | 🇨🇦 Canada | |
| 9 | Grand Canyon National Park | 🇺🇸 United States | |
| 10 | Yellowstone National Park | 🇺🇸 United States | |
| 11 | Pyrénées National Park | 🇫🇷 France |
With luck
About 10% of wildlife watchers report an Arctic Blue sighting in Rocky Mountain National Park on a given day, based on 60 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 21st most-seen of the 191 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.
July and August
In those months about 20% of wildlife watchers report an Arctic Blue in Rocky Mountain National Park on a given day, against under 5% in October to May, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Arctic 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.
3rd of 11
Of the 11 parks where we can rate Arctic Blue sightings, Rocky Mountain National Park ranks 3rd at about 10%. The best odds are in Vanoise National Park (France, about 20%) and Mercantour National Park (France, about 20%).
Same family: Lycaenidae
The closest relatives of the Arctic Blue that you can see in Rocky Mountain National Park (family Lycaenidae, Gossamer-winged Butterflies) are Greenish Blue (about 10%), Dorcas Copper (about 10%) and Western Pine Elfin (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Arctic Blue is recorded against all the insects logged in Rocky Mountain National Park (60 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.
