Asemosyrphus polygrammus
In 3 days ~10% in a week ~30%
Asemosyrphus polygrammus, the common sickleleg or northern sickleleg, is a species of rat-tail maggot fly in the family Syrphidae. This species was formerly a member of the genus Lejops. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Yosemite National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sacramento | 🇺🇸 United States | |
| 2 | Los Angeles | 🇺🇸 United States | |
| 3 | San Francisco | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Northern Sickleleg sighting in Yosemite National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 192nd most-seen of the 227 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
July and October
In those months about 10% of wildlife watchers report a Northern Sickleleg in Yosemite National Park on a given day, against under 5% in August–September and November–June, the lowest months. Those are among Yosemite National Park's driest months, with about 35 mm of rain a month against 220 mm in January.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Northern Sickleleg sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Only Yosemite National Park, in our data
Yosemite National Park is the only park on Wallace's Line with enough records to rate Northern Sickleleg sightings: under 5% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Northern Sickleleg is recorded against all the insects logged in Yosemite National Park (6 verified sightings from 2019 to 2026), 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.
