Colias meadii
In 3 days ~30% in a week ~60%
Colias meadii, the Mead's sulphur, is a butterfly in the family Pieridae found in North America. Its range includes the Rocky Mountains in Canada and the United States. Flight period is from July to August. It inhabits arctic-alpine tundra and rocky slopes, in high mountain areas at or near tree lines.
Wingspan is from 35 to 44 mm. Larvae feed on Trifolium spp. Astragalus alpinus, Oxytropis deflexa and Vicia americana. Adults feed on flower nectar from alpine sunflower and asters. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rocky Mountain National Park | 🇺🇸 United States |
More parks will be added in future updates.
With luck
About 10% of wildlife watchers report a Mead's Sulphur sighting in Rocky Mountain National Park on a given day, based on 49 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 25th most-seen of the 191 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.
July and August
In those months about 20% of wildlife watchers report a Mead's Sulphur in Rocky Mountain National Park on a given day, against under 5% in September to June, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Mead's Sulphur sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Rocky Mountain National Park, in our data
Rocky Mountain National Park is the only park on Wallace's Line with enough records to rate Mead's Sulphur sightings: about 10% of wildlife watchers there report one on a given day.
Same genus: Colias
The closest relatives of the Mead's Sulphur that you can see in Rocky Mountain National Park (genus Colias, Clouded Yellows) are Queen Alexandra’s Sulphur (about 10%), Colias scudderi (about 10%) and Clouded Sulphur (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Mead's Sulphur is recorded against all the insects logged in Rocky Mountain National Park (49 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.
