Somula decora
In 3 days ~20% in a week ~50%
Somula decora, commonly known as the spotted wood fly, is an uncommon species of syrphid fly observed in central to eastern North America. Hoverflies can remain nearly motionless in flight. 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 live in decaying wood. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Toronto | 🇨🇦 Canada | |
| 2 | Boston | 🇺🇸 United States | |
| 3 | Montreal | 🇨🇦 Canada | |
| 4 | Washington | 🇺🇸 United States | |
| 5 | New York City | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Spotted Wood Fly sighting in Shenandoah National Park on a given day, based on 29 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 156th 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 50%, if each day is a fresh chance.
April and May
In those months about 20% of wildlife watchers report a Spotted Wood Fly in Shenandoah National Park on a given day, against under 5% in July to March, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Spotted Wood Fly sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Only Shenandoah National Park, in our data
Shenandoah National Park is the only park on Wallace's Line with enough records to rate Spotted Wood Fly sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Syrphidae
The closest relatives of the Spotted Wood Fly 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 Spotted Wood Fly is recorded against all the insects logged in Shenandoah National Park (29 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.
