Brephidium exilis
In 3 days ~10% in a week ~20%
The western pygmy blue (Brephidium exilis or Brephidium exile) is one of the smallest butterflies in the world and the smallest in North America. It has reached Hawaii, as well as the Persian Gulf, including Kuwait, eastern Saudi Arabia, Bahrain and the United Arab Emirates.
The upperside is copper brown with dull blue at the bases of both wings. The underside of the hindwing is copper brown with white at the base; the fringe mostly white, with 3 small black spots near base, and a row of black spots at outer margin. The wingspan is 12–20 mm.
Males establish a territory in which they look for receptive females to mate with. After mating, females lay eggs on all parts of the host plant, oftenmost on the uppersides of leaves. The caterpillars eat all parts of the plant; host species include Pigweed (Chenopodium album), saltbush species (Atriplex), and others in the goosefoot family (Chenopodiaceae). Adult imagos appear in July–September in the north, while it appears year round in South Texas. Adults feed on nectar only.
This butterfly can be found in alkaline areas such as deserts, salt marshes, and barren areas. They are... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Death Valley National Park | 🇺🇸 United States | |
| 2 | Bahía de Loreto National Park | 🇲🇽 Mexico | |
| 3 | Joshua Tree National Park | 🇺🇸 United States | |
| 4 | Saguaro National Park | 🇺🇸 United States | |
| 5 | Ría Lagartos Biosphere Reserve | 🇲🇽 Mexico | |
| 6 | Channel Islands National Park | 🇺🇸 United States | |
| 7 | Big Bend National Park | 🇺🇸 United States | |
| 8 | Zion National Park | 🇺🇸 United States | |
| 9 | Grand Canyon National Park | 🇺🇸 United States | |
| 10 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Manama | 🇧🇭 Bahrain | |
| 2 | Abu Dhabi | 🇦🇪 United Arab Emirates | |
| 3 | Ciudad Juárez | 🇲🇽 México | |
| 4 | Dubai | 🇦🇪 United Arab Emirates | |
| 5 | Tijuana | 🇲🇽 México | |
| 6 | Kuwait City | 🇰🇼 Kuwait | |
| 7 | Torreón | 🇲🇽 México | |
| 8 | Mesa | 🇺🇸 United States | |
| 9 | Phoenix | 🇺🇸 United States | |
| 10 | Las Vegas | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Western Pygmy-Blue sighting in Cumbres de Monterrey National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 344th most-seen of the 431 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.
October and November
In those months about 10% of wildlife watchers report a Western Pygmy-Blue in Cumbres de Monterrey National Park on a given day, against under 5% in December to September, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Western Pygmy-Blue sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
10th of 10
Of the 10 parks where we can rate Western Pygmy-Blue sightings, Cumbres de Monterrey National Park ranks 10th at under 5%. The best odds are in Death Valley National Park (United States, about 40%), Bahía de Loreto National Park (Mexico, about 30%) and Joshua Tree National Park (United States, about 20%).
Same family: Lycaenidae
The closest relatives of the Western Pygmy-Blue that you can see in Cumbres de Monterrey National Park (family Lycaenidae, Gossamer-winged Butterflies) are Reakirt's Blue (about 10%), Ceraunus Blue (about 10%) and Falcate Emesis (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Pygmy-Blue is recorded against all the insects logged in Cumbres de Monterrey National Park (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.
