Scaeva affinis
In 3 days ~20% in a week ~40%
Scaeva affinis, commonly known as the white-bowed smoothwing, is a species of hoverfly found in western North America. The larval form feeds voraciously on aphids. Scaeva affinis is the only Scaeva likely to be encountered in the Nearctic realm, where it is common in the west and rare in the east. This species is believed to be migratory. In 1823, Thomas Say originally described it as "tergum black with three yellow lunules on each side...inhabits Arkansa." S. affinis was later combined with (and then determined to be a distinct species and was split back off from) Scaeva pyrastri. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Banff National Park | 🇨🇦 Canada | |
| 2 | Jasper National Park | 🇨🇦 Canada | |
| 3 | Zion National Park | 🇺🇸 United States | |
| 4 | Glacier National Park | 🇺🇸 United States | |
| 5 | Grand Teton National Park | 🇺🇸 United States | |
| 6 | Yosemite National Park | 🇺🇸 United States | |
| 7 | Joshua Tree National Park | 🇺🇸 United States | |
| 8 | Olympic National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sacramento | 🇺🇸 United States | |
| 2 | Calgary | 🇨🇦 Canada | |
| 3 | Salt Lake City | 🇺🇸 United States | |
| 4 | Portland | 🇺🇸 United States | |
| 5 | Edmonton | 🇨🇦 Canada | |
| 6 | Vancouver | 🇨🇦 Canada | |
| 7 | Seattle | 🇺🇸 United States | |
| 8 | San Francisco | 🇺🇸 United States | |
| 9 | Los Angeles | 🇺🇸 United States | |
| 10 | San Diego | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a White-Bowed Smoothwing sighting in Vancouver on a given day, based on 109 verified sightings from GBIF citizen-science data. It is the 66th most-seen of the 482 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
April–July and September–October
In those months about 10% of wildlife watchers report a White-Bowed Smoothwing in Vancouver on a given day, against under 5% in August and November–March, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most White-Bowed Smoothwing sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 13 cities where we can rate White-Bowed Smoothwing sightings, Vancouver ranks 6th at about 10%, level with the leaders once rounded. The best odds are in Sacramento (United States, about 10%), Calgary (Canada, about 10%) and Salt Lake City (United States, about 10%).
Same family: Syrphidae
The closest relatives of the White-Bowed Smoothwing that you can see in Vancouver (family Syrphidae, Hover Flies) are Black-Margined Flower Fly (about 10%), Common Drone Fly (about 10%) and Eurasian Drone Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the White-Bowed Smoothwing is recorded against all the insects logged in Vancouver (109 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.
