Somula decora
In 3 days ~10% in a week ~20%
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 |
Rare
Under 5% of wildlife watchers report a Spotted Wood Fly sighting in Boston on a given day, based on 8 verified sightings from GBIF citizen-science data. It is the 888th most-seen of the 1200 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 Spotted Wood Fly in Boston on a given day, so our monthly data shows no clear season.
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.
Among the best
Of the 5 cities where we can rate Spotted Wood Fly sightings, Boston ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Toronto (Canada, under 5%).
Same family: Syrphidae
The closest relatives of the Spotted Wood Fly that you can see in Boston (family Syrphidae, Hover Flies) are Margined Calligrapher (about 20%), Eastern Calligrapher (about 20%) and Transverse-Banded Flower Fly (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 Boston (8 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.
