Colias behrii
In 3 days ~10% in a week ~20%
Colias behrii, the Behr's sulphur or Sierra green sulfur, is a butterfly in the family Pieridae. It is endemic to California's Sierra Nevada from Tuolumne County south to Tulare County. The wingspan is 35–42 mm (1.4–1.7 in). Adults are on wing from July to August. They feed on flower nectar.
The larvae feed on Vaccinium species and Gentiana newberryi. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Yosemite National Park | 🇺🇸 United States | |
| 2 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Sierra Sulphur sighting in Sequoia and Kings Canyon National Parks on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 161st most-seen of the 161 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
July and August
In those months about 10% of wildlife watchers report a Sierra Sulphur in Sequoia and Kings Canyon National Parks on a given day, against under 5% in September to June, the lowest months. Those are among Sequoia and Kings Canyon National Parks's driest months, with about 25 mm of rain a month against 190 mm in January.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Sierra Sulphur 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 Sierra Sulphur sightings, Sequoia and Kings Canyon National Parks ranks 2nd at under 5%. The best odds are in Yosemite National Park (United States, about 20%).
GBIF citizen-science records
It is estimated from how often the Sierra Sulphur is recorded against all the insects logged in Sequoia and Kings Canyon National Parks (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.
