Tropidia quadrata
In 3 days ~10%
Tropidia quadrata, commonly known as the common thickleg fly, is a common species of syrphid fly observed across the north-central United states and southern Canada. 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 are aquatic. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 2 | Toronto | 🇨🇦 Canada | |
| 3 | Denver | 🇺🇸 United States | |
| 4 | Boston | 🇺🇸 United States | |
| 5 | Montreal | 🇨🇦 Canada | |
| 6 | Chicago | 🇺🇸 United States | |
| 7 | San Francisco | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Common Thick-Leg Fly sighting in San Francisco on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 480th most-seen of the 737 insects we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Common Thick-Leg Fly in San Francisco on a given day, so our monthly data shows no clear season.
Among the best
Of the 7 cities where we can rate Common Thick-Leg Fly sightings, San Francisco ranks 7th at under 5%, level with the leaders once rounded. The best odds are in Minneapolis [Saint Paul] (United States, under 5%), Toronto (Canada, under 5%) and Denver (United States, under 5%).
Same family: Syrphidae
The closest relatives of the Common Thick-Leg Fly that you can see in San Francisco (family Syrphidae, Hover Flies) are Oblique Streaktail (about 10%), Eurasian Drone Fly (about 10%) and Thick-Legged Hover Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Common Thick-Leg Fly is recorded against all the insects logged in San Francisco (10 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.
