Tabanus punctifer
In 3 days ~10%
Tabanus punctifer, commonly known as the western horse fly, is a species of horse fly in the family Tabanidae. This species of horse fly is approximately 20.5 mm (0.8 in) long. They are typically found throughout the southern and western parts of the United States. They can be found between Utah and Mexico, and between California and Texas. The thorax is covered with long hairs that give it a creamy white color, while the abdomen is completely black. Much like other horse fly species, the Tabanus punctifer female requires a blood meal for the development of their eggs. Females will bite horses, livestock, and humans, making them vectors of disease for pathogens and parasites.
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| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Death Valley National Park | 🇺🇸 United States | |
| 2 | Saguaro National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Salt Lake City | 🇺🇸 United States | |
| 2 | Sacramento | 🇺🇸 United States | |
| 3 | Denver | 🇺🇸 United States | |
| 4 | Phoenix | 🇺🇸 United States | |
| 5 | San Francisco | 🇺🇸 United States | |
| 6 | Los Angeles | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Western Black Horse Fly sighting in San Francisco on a given day, based on 15 verified sightings from GBIF citizen-science data. It is the 404th 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 Western Black Horse Fly in San Francisco on a given day, so our monthly data shows no clear season.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Western Black Horse 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.
5th of 6
Of the 6 cities where we can rate Western Black Horse Fly sightings, San Francisco ranks 5th at under 5%. The best odds are in Salt Lake City (United States, about 10%), Sacramento (United States, under 5%) and Denver (United States, under 5%).
Same order: Diptera
The closest relatives of the Western Black Horse Fly that you can see in San Francisco (order Diptera, Flies) are Oblique Streaktail (about 10%), Eurasian Drone Fly (about 10%) and Coyote Brush Bud Gall Midge (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Black Horse Fly is recorded against all the insects logged in San Francisco (15 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.
