Erynnis horatius
In 3 days ~10% in a week ~20%
Erynnis horatius, commonly known as Horace's duskywing, is a species of butterfly in the family Hesperiidae. It is found in the United States from Massachusetts to Florida, and west to eastern South Dakota, the Gulf Coast, south-eastern Utah, Colorado, north-eastern Arizona, and New Mexico. It is listed as a species of special concern in the US state of Connecticut.
Fringes are brown. Upperside of male forewing is dark brown with little contrast and no white overscaling. Upperside of female forewing is light brown with a contrasting pattern and large transparent spots. Underside of hindwing is usually without two spots below the apex. The male has a costal fold containing yellow scent scales; the female has a patch of scent scales on the 7th abdominal segment. The wingspan is 36–49 mm.
There are two generations in the north, with adults on the wing from April to September; there are three generations in the deep south and Texas, with adults on the wing from January to November. Adults prefer open woodlands and edges, clearings, fence rows, wooded swamps, power-line right-of-ways, open fields and roadsides.
Caterpillars are hosted by various oak species such as willow oak (Quercus phellos), northern red oak (Q. velutina), scrub oak (Q. ilicifolia), water oak (Q. nigra), post oak (Q. stellata), and live oak (Q. virginiana). Adults consume nectar from flowers up to about 4.5 feet (1.4 m) above ground level, including those of dogbane, buttonbush, sneezeweed, goldenrod, peppermint, boneset, and winter cress. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Congaree National Park | 🇺🇸 United States | |
| 2 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 3 | Shenandoah National Park | 🇺🇸 United States | |
| 4 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Miami | 🇺🇸 United States | |
| 2 | San Antonio | 🇺🇸 United States | |
| 3 | Austin | 🇺🇸 United States | |
| 4 | Orlando | 🇺🇸 United States | |
| 5 | Dallas | 🇺🇸 United States | |
| 6 | Houston | 🇺🇸 United States | |
| 7 | Washington | 🇺🇸 United States | |
| 8 | Baltimore | 🇺🇸 United States | |
| 9 | Philadelphia | 🇺🇸 United States | |
| 10 | New York City | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Horace's Duskywing sighting in Chicago on a given day, based on 9 verified sightings from GBIF citizen-science data. It is the 669th most-seen of the 978 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.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Horace's Duskywing in Chicago on a given day, so our monthly data shows no clear season.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Horace's Duskywing sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
11th of 11
Of the 11 cities where we can rate Horace's Duskywing sightings, Chicago ranks 11th at under 5%. The best odds are in Miami (United States, about 20%), San Antonio (United States, about 10%) and Austin (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Horace's Duskywing is recorded against all the insects logged in Chicago (9 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.
