Urophora cardui
In 3 days ~10% in a week ~20%
Urophora cardui or the Canada thistle gall fly is a fruit fly which, contrary to its common name, is indigenous to Central Europe from the United Kingdom east to near the Crimea, and from Sweden south to the Mediterranean. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Wadden Sea National Park | 🇩🇪 Germany |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Manchester | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Toronto | 🇨🇦 Canada | |
| 4 | London | 🇬🇧 United Kingdom | |
| 5 | Denver | 🇺🇸 United States | |
| 6 | Portland | 🇺🇸 United States | |
| 7 | Montreal | 🇨🇦 Canada | |
| 8 | Chicago | 🇺🇸 United States | |
| 9 | Baltimore | 🇺🇸 United States | |
| 10 | Saint Petersburg | 🇷🇺 Russia |
Rare
Under 5% of wildlife watchers report a Thistle Stem Gall Fly sighting in Chicago on a given day, based on 36 verified sightings from GBIF citizen-science data. It is the 293rd most-seen of the 978 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 Thistle Stem Gall Fly in Chicago on a given day, so our monthly data shows no clear season.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Thistle Stem Gall Fly sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
8th of 13
Of the 13 cities where we can rate Thistle Stem Gall Fly sightings, Chicago ranks 8th at under 5%. The best odds are in Manchester (United Kingdom, about 10%), Birmingham (United Kingdom, about 10%) and Toronto (Canada, about 10%).
GBIF citizen-science records
It is estimated from how often the Thistle Stem Gall Fly is recorded against all the insects logged in Chicago (36 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.
