Epistrophe grossulariae
In 3 days ~30% in a week ~50%
Epistrophe grossulariae is a Holarctic species of hoverfly. External images For terms see Morphology of Diptera Wing length 9-12·25 mm. Thorax dull greenish. Tergite 4 with entire yellow band. At least anterior femora dark at base, sometimes hind also. Frons black above lunule and at least half black-haired. Female has a bronzy-green area on upper part of frons. Yellow bands on tergites 3 and 4 straight. Tergite 5 with black band.
Male genitalia are figured by Hippa (1968). The larva is illustrated by Rotheray (1993) Palaearctic and Nearctic Fennoscandia South to Spain, Italy and Yugoslavia. Ireland eastwards through Turkey Russia to Kamchatka. In North America from Alaska to Quebec and South to California.
Habitat is deciduous woodland, particularly along rivers and streams, Salix swamp woodland, alpine grassland. Found in clearings, tracksides and beside streams. Flowers visited include white umbellifers, Centaurea, Cirsium, Filipendula, Geranium, Knautia, Rhododendron, Rubus, Sambucus nigra, Succisa,
Valeriana. The flight period is end June to September. The larva feeds on aphids. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 3 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 4 | Acadia National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Manchester | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Leeds | 🇬🇧 United Kingdom | |
| 4 | Liverpool | 🇬🇧 United Kingdom | |
| 5 | Edmonton | 🇨🇦 Canada | |
| 6 | London | 🇬🇧 United Kingdom | |
| 7 | Boston | 🇺🇸 United States | |
| 8 | Moscow | 🇷🇺 Russia | |
| 9 | Montreal | 🇨🇦 Canada | |
| 10 | Vancouver | 🇨🇦 Canada |
With luck
About 10% of wildlife watchers report a Black-Horned Smoothtail sighting in Great Smoky Mountains National Park on a given day, based on 46 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 123rd most-seen of the 822 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
September
In that month about 30% of wildlife watchers report a Black-Horned Smoothtail in Great Smoky Mountains National Park on a given day, against under 5% in December to June, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Black-Horned Smoothtail sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 4 parks where we can rate Black-Horned Smoothtail sightings, Great Smoky Mountains National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Shenandoah National Park (United States, about 10%).
Same family: Syrphidae
The closest relatives of the Black-Horned Smoothtail that you can see in Great Smoky Mountains National Park (family Syrphidae, Hover Flies) are Eastern Calligrapher (about 20%), Margined Calligrapher (about 10%) and Common Drone Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Black-Horned Smoothtail is recorded against all the insects logged in Great Smoky Mountains National Park (46 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.
