Bug FAQSierra Sulphur
Colias behrii · Order: Lepidoptera · Family: Pieridae
Also called: Behr's Sulphur, Sierra Green Sulfur
The Sierra sulphur butterfly, Colias behrii, belongs to the Pieridae family and measures about 35 to 42 mm across the wings. It lives only in California’s Sierra Nevada, from Tuolumne County down to Tulare County, and adults are active in July and August. Adults sip flower nectar, while the caterpillars feed on Vaccinium plants and Gentiana newberryi.
Source: Wikipedia
How to recognize it
Colias behrii, known as Behr's sulphur or Sierra green sulphur, is a butterfly in the Pieridae family.
Source: Wikipedia
Size
Its wingspan ranges from 35 to 42 mm (about 1.4 to 1.7 in).
Source: Wikipedia
What it eats
Adult butterflies feed on flower nectar. Caterpillars eat leaves of Vaccinium species and Gentiana newberryi.
Source: Wikipedia
Life cycle
Adults are on the wing from July through August.
Source: Wikipedia
When you see it
The flight period for adults occurs in July and August.
Source: Wikipedia
Where it comes from
It is native to the Sierra Nevada region of California.
Source: Wikipedia
Where it is found in the US
Recorded in 2 of 51 states and DC. Most records: California, Wyoming.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: endemic in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When can I see Sierra sulphur butterflies?
Adults are active and flying in July and August.
Source: Wikipedia
What do the caterpillars eat?
The larvae feed on Vaccinium plants and Gentiana newberryi.
Source: Wikipedia
Where does this butterfly live?
It is found only in California’s Sierra Nevada, from Tuolumne County down to Tulare County.
Source: Wikipedia
Same family (Pieridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Colias_behrii
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-25 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-25.