Blera scitula
In 3 days ~20% in a week ~40%
Blera scitula, the western wood fly, is an uncommon species of syrphid fly first officially described by Williston in 1882. Hoverflies get their names from the ability to remain nearly motionless while in flight. The adults are also known as flower flies, for they are commonly found around and on the flowers from which they get both energy-giving nectar and protein-rich pollen. The larvae of Blera are of the rat-tailed type, feeding on exuding sap or in the rot holes of trees.
This is a Nearctic species found on the western coastal area of North America. External image For terms see Morphology of Diptera. External images Size 10 to 13 mm. Head The frontal triangle is opaque yellow, The vertical triangle is black, with black pile. In the female the frons is moderately narrowed above and yellow on the lower fourth, shining greenish black elsewhere except thinly reddish pollinose in front of the ocelli. The pile is black. The pile is longer on the ocellar triangle and is yellow at the vertex. The face is yellow, with yellow pollen and a prominent rounded tubercle in the middle. The gena are shining black. The antennae are red with the flagellum... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Bear Rainforest | 🇨🇦 Canada | |
| 2 | Olympic National Park | 🇺🇸 United States | |
| 3 | Pacific Rim National Park Reserve | 🇨🇦 Canada |
With luck
About 10% of wildlife watchers report a Western Wood Fly sighting in Olympic National Park on a given day, based on 19 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 72nd most-seen of the 207 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.
June to August
In those months about 10% of wildlife watchers report a Western Wood Fly in Olympic National Park on a given day, against under 5% in September to May, the lowest months. Those are among Olympic National Park's driest months, with about 55 mm of rain a month against 370 mm in November.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Western Wood Fly sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 3 parks where we can rate Western Wood Fly sightings, Olympic National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Great Bear Rainforest (Canada, about 10%).
Same family: Syrphidae
The closest relatives of the Western Wood Fly that you can see in Olympic National Park (family Syrphidae, Hover Flies) are Common Drone Fly (about 10%), Western Pond Fly (about 10%) and Black-Margined Flower Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Wood Fly is recorded against all the insects logged in Olympic National Park (19 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.
