Celastrina ladon
In 3 days ~10% in a week ~30%
Celastrina ladon, the spring azure or echo blue, is a butterfly of the family Lycaenidae. It is found in North America from Alaska and Canada south of the tundra, through most of the United States except the Texas coast, southern plain and peninsula Florida; south in the mountains to Colombia, also on Molokai island, Hawaii.
Since the publication of a monograph on the Lycaenopsis group of lycaenid genera in 1983 by Eliot & Kawazoe, C. ladon has been considered by some taxonomic authorities to be a subspecies of C. argiolus (Linnaeus, 1758). Other authorities still consider C. ladon and related species C. neglecta and C. serotina to be "full" species.
Its wingspan is 22–35 millimetres (0.87–1.38 in). The metallic blue wings have a black margin in females. The undersides of the wings are white with speckles. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States | |
| 2 | Yosemite National Park | 🇺🇸 United States | |
| 3 | Channel Islands National Park | 🇺🇸 United States | |
| 4 | Redwood National Park | 🇺🇸 United States | |
| 5 | Guadalupe Mountains National Park | 🇺🇸 United States | |
| 6 | Los Quetzales National Park | 🇨🇷 Costa Rica | |
| 7 | Grand Canyon National Park | 🇺🇸 United States | |
| 8 | Olympic National Park | 🇺🇸 United States | |
| 9 | Saguaro National Park | 🇺🇸 United States | |
| 10 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 11 | Great Bear Rainforest | 🇨🇦 Canada | |
| 12 | Grand Teton National Park | 🇺🇸 United States | |
| 13 | Rocky Mountain National Park | 🇺🇸 United States | |
| 14 | Cumbres de Monterrey National Park | 🇲🇽 Mexico | |
| 15 | Zion National Park | 🇺🇸 United States | |
| 16 | Pacific Rim National Park Reserve | 🇨🇦 Canada | |
| 17 | Glacier National Park | 🇺🇸 United States | |
| 18 | Big Bend National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Toluca | 🇲🇽 México | |
| 2 | Seattle | 🇺🇸 United States | |
| 3 | Mexico City | 🇲🇽 México | |
| 4 | San Francisco | 🇺🇸 United States | |
| 5 | Vancouver | 🇨🇦 Canada | |
| 6 | Philadelphia | 🇺🇸 United States | |
| 7 | Portland | 🇺🇸 United States | |
| 8 | Chicago | 🇺🇸 United States | |
| 9 | Boston | 🇺🇸 United States | |
| 10 | Washington | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Spring Azure sighting in Big Bend National Park on a given day, based on 11 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 283rd most-seen of the 329 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.
April–May and August
In those months about 10% of wildlife watchers report a Spring Azure in Big Bend National Park on a given day, against under 5% in June–July and September–March, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Spring Azure sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
18th of 18
Of the 18 parks where we can rate Spring Azure sightings, Big Bend National Park ranks 18th at under 5%. The best odds are in Sequoia and Kings Canyon National Parks (United States, about 30%), Yosemite National Park (United States, about 20%) and Channel Islands National Park (United States, about 20%).
Same family: Lycaenidae
The closest relatives of the Spring Azure that you can see in Big Bend National Park (family Lycaenidae, Gossamer-winged Butterflies) are Reakirt's Blue (about 30%), Gray Hairstreak (about 30%) and Marine Blue (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Spring Azure is recorded against all the insects logged in Big Bend National Park (11 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.
