Hemiargus ceraunus
In 3 days ~10% in a week ~20%
Hemiargus ceraunus, the Ceraunus blue, is a species of butterfly in the family Lycaenidae. The species was first described by Johan Christian Fabricius in 1793. It is found in the southwestern United States, southern Texas, Florida and the Florida Keys south through the West Indies, Mexico and Central America to South America. Strays may be found in North Carolina, Missouri, Kansas and Nevada. The habitat consists of open woodland, desert scrub, dunes, pastures, road edges and vacant lots.
The wingspan is 20–30 mm. Adults are on wing year round in Texas and southern Florida and in late summer in other parts of the range. Adults feed on flower nectar. The larvae feed on the flowers and seedpods of various woody legumes, including Chamaecrista fasciculata, Abrus precatorius and Prosopis species. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Padre Island National Seashore | 🇺🇸 United States | |
| 2 | Ría Lagartos Biosphere Reserve | 🇲🇽 Mexico | |
| 3 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 4 | Bahía de Loreto National Park | 🇲🇽 Mexico | |
| 5 | Everglades National Park | 🇺🇸 United States | |
| 6 | Cabo Pulmo National Park | 🇲🇽 Mexico | |
| 7 | Saguaro National Park | 🇺🇸 United States | |
| 8 | Joshua Tree National Park | 🇺🇸 United States | |
| 9 | Big Cypress National Preserve | 🇺🇸 United States | |
| 10 | Gandoca-Manzanillo Wildlife Refuge | 🇨🇷 Costa Rica | |
| 11 | Cumbres de Monterrey National Park | 🇲🇽 Mexico | |
| 12 | Cañón del Sumidero National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Santo Domingo | 🇩🇴 Dominican Republic | |
| 2 | San Antonio | 🇺🇸 United States | |
| 3 | San Pedro Sula | 🇭🇳 Honduras | |
| 4 | Torreón | 🇲🇽 México | |
| 5 | Monterrey | 🇲🇽 México | |
| 6 | Austin | 🇺🇸 United States | |
| 7 | Miami | 🇺🇸 United States | |
| 8 | Mesa | 🇺🇸 United States | |
| 9 | Phoenix | 🇺🇸 United States | |
| 10 | Orlando | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Ceraunus Blue sighting in San José on a given day, based on 6 verified sightings from GBIF citizen-science data. It is the 210th most-seen of the 239 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.
January–February and April
In those months about 10% of wildlife watchers report a Ceraunus Blue in San José on a given day, against under 5% in March and May–December, the lowest months. Those are among San José's driest months, with about 45 mm of rain a month against 300 mm in October.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Ceraunus Blue sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
15th of 18
Of the 18 cities where we can rate Ceraunus Blue sightings, San José ranks 15th at under 5%. The best odds are in Santo Domingo (Dominican Republic, about 20%), San Antonio (United States, about 20%) and San Pedro Sula (Honduras, about 10%).
Same family: Lycaenidae
The closest relatives of the Ceraunus Blue that you can see in San José (family Lycaenidae, Gossamer-winged Butterflies) are Red-Bordered Pixie (about 10%), Cassius Blue (about 10%) and Sky-Blue Hairstreak (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Ceraunus Blue is recorded against all the insects logged in San José (6 verified sightings), 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.
