Strymon melinus
In 3 days ~20% in a week ~40%
The gray hairstreak (Strymon melinus) is also called the bean lycaenid or cotton square borer. It is a member of the Lycaenidae family, known as the gossamer-winged butterflies and the second-largest family of butterflies. It is one of the most common hairstreaks in North America, ranging over nearly the entire continent. It also occurs throughout Central America and in northern South America.
The adult gray hairstreak has a wingspan of 20–32 millimetres (0.79–1.26 in). The upper sides of the wings are gray with an orange spot on the hind margin. The underside of the wings are a lighter gray with white and black lines and orange and blue marginal spots near the hind-wings' tail-like extensions. These extensions twitch while at rest, and may imitate a separate head to encourage predators to go for the wings, potentially allowing the insect to survive.
Caterpillars are green with markings on the sides, covered in short yellow hairs. Like other caterpillars in the Lycaenidae family, S. melinus are attended by ants in a behavior known as myrmecophily. The gray hairstreak lives in a wide range of habitats ranging from tropical forests and mountains... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Austin | 🇺🇸 United States | |
| 2 | Dallas | 🇺🇸 United States | |
| 3 | Valencia | 🇻🇪 Venezuela | |
| 4 | San Antonio | 🇺🇸 United States | |
| 5 | Sacramento | 🇺🇸 United States | |
| 6 | Portland | 🇺🇸 United States | |
| 7 | Tijuana | 🇲🇽 México | |
| 8 | Mesa | 🇺🇸 United States | |
| 9 | San Francisco | 🇺🇸 United States | |
| 10 | San Diego | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Gray Hairstreak sighting in Yosemite National Park on a given day, based on 21 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 75th most-seen of the 227 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
July
In that month about 20% of wildlife watchers report a Gray Hairstreak in Yosemite National Park on a given day, against under 5% in October to May, the lowest months. That is one of Yosemite National Park's driest months, with about 25 mm of rain against 220 mm in January.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Gray Hairstreak sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
18th of 24
Of the 24 parks where we can rate Gray Hairstreak sightings, Yosemite National Park ranks 18th at about 10%. The best odds are in Big Bend National Park (United States, about 30%), Channel Islands National Park (United States, about 20%) and Congaree National Park (United States, about 20%).
Same genus: Strymon
The closest relatives of the Gray Hairstreak that you can see in Yosemite National Park (genus Strymon, Scrub-Hairstreaks) are Strymon acadica (about 10%) and Strymon saepium (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Gray Hairstreak is recorded against all the insects logged in Yosemite National Park (21 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.
