Icaricia shasta
In 3 days ~40% in a week ~70%
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 |
Possible
About 20% of wildlife watchers report a Shasta Blue sighting in Yosemite National Park on a given day, based on 199 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 15th most-seen of the 227 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
July
In that month about 30% of wildlife watchers report a Shasta Blue in Yosemite National Park on a given day, against under 5% in November to June, the lowest months. That is one of Yosemite National Park's driest months, with about 25 mm of rain against 220 mm in January.
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.
Yes
Of the 2 parks where we can rate Shasta Blue sightings, Yosemite National Park has the highest daily chance: about 20%. Next come Rocky Mountain National Park (United States, under 5%).
Same genus: Icaricia
The closest relatives of the Shasta Blue that you can see in Yosemite National Park (genus Icaricia) are Greenish Blue (about 20%), Acmon 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 Yosemite National Park (199 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.
