Tropidia albistylum
In 3 days ~10% in a week ~20%
Tropidia albistylum (Macquart, 1847), the Yellow-thighed Thickleg Fly, is a rare species of syrphid fly observed across the eastern and central United States. 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 | Washington | 🇺🇸 United States | |
| 2 | Boston | 🇺🇸 United States | |
| 3 | New York City | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Yellow-Thighed Thick-Leg Fly sighting in Washington on a given day, based on 38 verified sightings from GBIF citizen-science data. It is the 537th most-seen of the 1807 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.
September
In that month about 10% of wildlife watchers report a Yellow-Thighed Thick-Leg Fly in Washington on a given day, against under 5% in October to August, the lowest months.
Yes
Of the 3 cities where we can rate Yellow-Thighed Thick-Leg Fly sightings, Washington has the highest daily chance: under 5%. Next come Boston (United States, under 5%) and New York City (United States, under 5%).
Same family: Syrphidae
The closest relatives of the Yellow-Thighed Thick-Leg Fly that you can see in Washington (family Syrphidae, Hover Flies) are Eastern Calligrapher (about 10%), Margined Calligrapher (about 10%) 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 Yellow-Thighed Thick-Leg Fly is recorded against all the insects logged in Washington (38 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.
