Colias nastes
In 3 days ~20% in a week ~30%
Colias nastes, the Labrador sulphur, is a butterfly in the family Pieridae. In Europe, it is found in the north of Norway and Sweden and on rare occasions in northern Finland. It is also found in North America, specifically in Alaska, Canada, and the Rocky Mountains, Washington, Montana and on Greenland. In Asia, it is found in the Altai Mountains, the border regions of Russia, China, Mongolia, Kazakhstan, the Sayan Mountains, the north of Siberia, and in the Chukotka Autonomous Okrug.
The wingspan is 31–45 mm. C. nastes is dark grey green with grey-black margins and red fringes. The female is more yellowish and has more distinct yellowish submarginal spots on both wings. The under surface of the forewing is impure whitish, with greenish-yellow scales, the rose-red fringes are conspicuous, the hindwing is yellowish green, lighter at the margin, the white median spot is bordered with red and distally to it is placed a diffuse red spot, the rose-red fringes are broader than on the forewing. The female has a somewhat lighter under surface and on the forewing some small black submarginal spots.
The butterfly flies from May to August depending on the location... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Jasper National Park | 🇨🇦 Canada | |
| 2 | Banff National Park | 🇨🇦 Canada |
With luck
About 10% of wildlife watchers report a Labrador Sulphur sighting in Banff National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 61st most-seen of the 105 insects we can rate there. Over three days the chance rises to about 20%, 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 Labrador Sulphur in Banff National Park on a given day, against under 5% in September to June, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Labrador Sulphur 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 2 parks where we can rate Labrador Sulphur sightings, Banff National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Jasper National Park (Canada, about 10%).
Same genus: Colias
The closest relatives of the Labrador Sulphur that you can see in Banff National Park (genus Colias, Clouded Yellows) are Christina Sulphur (about 10%), Clouded Sulphur (about 10%) and Skinner's Pelidne Sulphur (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Labrador Sulphur is recorded against all the insects logged in Banff 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.
