Helophilus latifrons
In 3 days ~10%
Helophilus latifrons (Loew, 1863), the Broad-headed Marsh Fly, is a species of syrphid fly observed throughout the United States, in lower Canada and the mountains on Mexico. 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 feeding on decaying vegetation. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Calgary | 🇨🇦 Canada | |
| 2 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 3 | Sacramento | 🇺🇸 United States | |
| 4 | Denver | 🇺🇸 United States | |
| 5 | Edmonton | 🇨🇦 Canada | |
| 6 | Montreal | 🇨🇦 Canada | |
| 7 | Toronto | 🇨🇦 Canada | |
| 8 | San Francisco | 🇺🇸 United States | |
| 9 | Los Angeles | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Broad-Headed Marsh Fly sighting in San Francisco on a given day, based on 7 verified sightings from GBIF citizen-science data. It is the 577th 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 Broad-Headed Marsh Fly in San Francisco on a given day, so our monthly data shows no clear season.
Among the best
Of the 9 cities where we can rate Broad-Headed Marsh Fly sightings, San Francisco ranks 8th at under 5%, level with the leaders once rounded. The best odds are in Calgary (Canada, under 5%), Minneapolis [Saint Paul] (United States, under 5%) and Sacramento (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Broad-Headed Marsh Fly is recorded against all the insects logged in San Francisco (7 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.
