Tabanus atratus
In 3 days ~40% in a week ~70%
Tabanus is a genus of biting horseflies of the family Tabanidae. Females have scissor-like mouthparts that are able to penetrate the skin of livestock animals. The horsefly can then extract and ingest the animal's blood. Horseflies of this genus are known to be potential vectors of anthrax, worms and trypanosomes. Some species, such as Tabanus bovinus, prefer bovine animals and are less harmful to humans. The genus contains hundreds of species and many species groups. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Padre Island National Seashore | 🇺🇸 United States | |
| 2 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 3 | Big Cypress National Preserve | 🇺🇸 United States | |
| 4 | Everglades National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Baltimore | 🇺🇸 United States | |
| 2 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 3 | Houston | 🇺🇸 United States | |
| 4 | Washington | 🇺🇸 United States | |
| 5 | Montreal | 🇨🇦 Canada | |
| 6 | Austin | 🇺🇸 United States | |
| 7 | Dallas | 🇺🇸 United States | |
| 8 | Chicago | 🇺🇸 United States | |
| 9 | Toronto | 🇨🇦 Canada | |
| 10 | Philadelphia | 🇺🇸 United States |
Possible
About 20% of wildlife watchers report a Black Horse Fly sighting in Padre Island National Seashore on a given day, based on 18 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 17th most-seen of the 74 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
August to October
In those months about 30% of wildlife watchers report a Black Horse Fly in Padre Island National Seashore on a given day, against under 5% in November to March, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most 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.
Yes
Of the 4 parks where we can rate Black Horse Fly sightings, Padre Island National Seashore has the highest daily chance: about 20%. Next come Merritt Island National Wildlife Refuge (United States, about 10%) and Big Cypress National Preserve (United States, about 10%).
Same order: Diptera
The closest relatives of the Black Horse Fly that you can see in Padre Island National Seashore (order Diptera, Flies) are Gallinipper (about 10%), Yellow-Shouldered Drone Fly (about 10%) and Bathroom Moth Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Black Horse Fly is recorded against all the insects logged in Padre Island National Seashore (18 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.
