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 Boston on a given day, based on 9 verified sightings from GBIF citizen-science data. It is the 783rd 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.
August
In that month about 10% of wildlife watchers report a Yellow-Thighed Thick-Leg Fly in Boston on a given day, against under 5% in September to July, the lowest months.
Among the best
Of the 3 cities where we can rate Yellow-Thighed Thick-Leg Fly sightings, Boston ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Washington (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Yellow-Thighed Thick-Leg Fly is recorded against all the insects logged in Boston (9 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.
