Icaricia shasta
In 3 days ~10% in a week ~30%
Icaricia shasta, the Shasta blue, is a butterfly of the family Lycaenidae. It is found from the northwestern United States to southern Saskatchewan and Alberta. The wingspan is 20–22 mm. Adults are on wing from June to August.
The larvae feed on Lupinus lyalli, Astragalus spatulatus, Astragalus calycosus, and Trifolium dasphyllum. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Yosemite National Park | 🇺🇸 United States | |
| 2 | Rocky Mountain National Park | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Shasta Blue sighting in Rocky Mountain National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 172nd most-seen of the 191 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
August
In that month about 10% of wildlife watchers report a Shasta Blue in Rocky Mountain National Park on a given day, against under 5% in September to July, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Shasta Blue sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Shasta Blue sightings, Rocky Mountain National Park ranks 2nd at under 5%. The best odds are in Yosemite National Park (United States, about 20%).
Same genus: Icaricia
The closest relatives of the Shasta Blue that you can see in Rocky Mountain National Park (genus Icaricia) are Greenish Blue (about 10%), Lupine Blue (about 10%) and Boisduval's Blue (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Shasta Blue is recorded against all the insects logged in Rocky Mountain National Park (6 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.
