Pterallastes thoracicus
In 3 days ~20% in a week ~40%
Pterallastes thoracicus, the goldenback fly, is an uncommon species of syrphid fly observed across central and eastern areas of the United States. Hoverflies can remain nearly motionless in flight while many are mimics of bees. The adults are also known as flower flies for they are commonly found on flowers, from which they get both energy-giving nectar and protein-rich pollen. The larvae of this species are unknown. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Washington | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Goldenback sighting in Shenandoah National Park on a given day, based on 15 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 267th most-seen of the 723 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.
October
In that month about 20% of wildlife watchers report a Goldenback in Shenandoah National Park on a given day, against under 5% in June–July and November–April, the lowest months.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Goldenback sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 parks where we can rate Goldenback sightings, Shenandoah National Park has the highest daily chance: about 10%. Next come Great Smoky Mountains National Park (United States, about 10%).
Same family: Syrphidae
The closest relatives of the Goldenback that you can see in Shenandoah National Park (family Syrphidae, Hover Flies) are Eastern Calligrapher (about 20%), Common Drone Fly (about 20%) and Black-Horned Smoothtail (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Goldenback is recorded against all the insects logged in Shenandoah National Park (15 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.
