Speyeria zerene
In 3 days ~10% in a week ~30%
Speyeria zerene, the zerene fritillary, is a butterfly found in the western portions of the United States and Canada. The species was first described by William Swainson in 1827. Speyeria zerene is a medium-sized butterfly whose length ranges from 25 to 28 mm, and the wingspan is about 55 mm. The body of the butterfly is black with orange brown on the upperside of the wings. Also on the underside are black veins with black spots. The undersides of the wings have silver metallic spots. The wings and the body are both covered in fine hairs.
The native range spread from Washington state to California. They are now found in Oregon and California. As of 2013, they were found in numbers in Alpine County, California, at the 9,000 foot (2,700 m) level in the Sierra Nevada range. The best habitats for the butterflies are coastal salt spray meadows, montane meadows, and stabilized dunes. The grasslands provide larval host plants which are a very important component of their habitat. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Glacier National Park | 🇺🇸 United States | |
| 2 | Olympic National Park | 🇺🇸 United States | |
| 3 | Yosemite National Park | 🇺🇸 United States | |
| 4 | Yellowstone National Park | 🇺🇸 United States | |
| 5 | Rocky Mountain National Park | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Zerene Fritillary sighting in Yosemite National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 148th most-seen of the 227 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.
July and August
In those months about 10% of wildlife watchers report a Zerene Fritillary in Yosemite National Park on a given day, against under 5% in September to June, the lowest months. Those are among Yosemite National Park's driest months, with about 25 mm of rain a month against 220 mm in January.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Zerene Fritillary sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 5 parks where we can rate Zerene Fritillary sightings, Yosemite National Park ranks 3rd at about 10%, level with the leaders once rounded. The best odds are in Glacier National Park (United States, about 10%) and Olympic National Park (United States, about 10%).
Same genus: Speyeria
The closest relatives of the Zerene Fritillary that you can see in Yosemite National Park (genus Speyeria) are Mormon Fritillary (about 20%), Great Basin Fritillary (about 10%) and Hydaspe Fritillary (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Zerene Fritillary is recorded against all the insects logged in Yosemite National Park (9 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.
