Pterallastes thoracicus
In 3 days ~20% in a week ~30%
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 Great Smoky Mountains National Park on a given day, based on 16 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 334th most-seen of the 822 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
May–June and August–November
In those months about 10% of wildlife watchers report a Goldenback in Great Smoky Mountains National Park on a given day, against under 5% in July and December–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.
Among the best
Of the 2 parks where we can rate Goldenback 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 Goldenback 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 Goldenback is recorded against all the insects logged in Great Smoky Mountains National Park (16 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.
