Atlides halesus
In 3 days ~30% in a week ~60%
The great purple hairstreak (Atlides halesus), also called the great blue hairstreak, is a common gossamer-winged butterfly species in parts of the United States. It is actually a Neotropical species; its North American range only includes the warm-temperate and subtropical parts of that continent, and it ranges southwards almost to the Isthmus of Panama. The type specimen, however, was shipped to Europe from the Colony of Virginia, probably around the time of the United States Declaration of Independence.
The common names refer to the butterfly's two main colors – dusky purple on the underside, and iridescent blue above. Particularly the males are very colorful in flight – brilliant blue and velvety black, with bright red and golden markings – but when sitting down they show their inconspicuous dusky purple underside. On each hindwing, there are two tails, with one short and one long tail, lending itself to the name "hairstreak". Several subspecies are recognized.
Its caterpillar larvae feed on the mistletoe genus Phoradendron. The wingspan on the adult butterfly ranges from 1.25 to 1.5 inches. Despite its common name "great purple hairstreak", this butterfly does... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Joshua Tree National Park | 🇺🇸 United States | |
| 2 | Guadalupe Mountains National Park | 🇺🇸 United States | |
| 3 | Saguaro National Park | 🇺🇸 United States | |
| 4 | Big Bend National Park | 🇺🇸 United States | |
| 5 | Bahía de Loreto National Park | 🇲🇽 Mexico | |
| 6 | Death Valley National Park | 🇺🇸 United States | |
| 7 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 8 | Yosemite National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Austin | 🇺🇸 United States | |
| 2 | San Antonio | 🇺🇸 United States | |
| 3 | Dallas | 🇺🇸 United States | |
| 4 | Las Vegas | 🇺🇸 United States | |
| 5 | Orlando | 🇺🇸 United States | |
| 6 | Sacramento | 🇺🇸 United States | |
| 7 | Phoenix | 🇺🇸 United States | |
| 8 | Monterrey | 🇲🇽 México | |
| 9 | Houston | 🇺🇸 United States | |
| 10 | San Francisco | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Great Purple Hairstreak sighting in Big Bend National Park on a given day, based on 24 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 68th most-seen of the 329 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.
August and September
In those months about 30% of wildlife watchers report a Great Purple Hairstreak in Big Bend National Park on a given day, against under 5% in December and January, the lowest months. Those are among Big Bend National Park's wettest months, with about 50 mm of rain a month against 10 mm in April.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Great Purple Hairstreak sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 8
Of the 8 parks where we can rate Great Purple Hairstreak sightings, Big Bend National Park ranks 4th at about 10%. The best odds are in Joshua Tree National Park (United States, about 30%), Guadalupe Mountains National Park (United States, about 20%) and Saguaro National Park (United States, about 10%).
Same family: Lycaenidae
The closest relatives of the Great Purple Hairstreak 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 Great Purple Hairstreak is recorded against all the insects logged in Big Bend National Park (24 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.
