Hippobosca equina
In 3 days ~10% in a week ~30%
Hippobosca equina, also known as the forest fly or New Forest fly, is a biting fly from the family Hippoboscidae. They are blood-feeding ectoparasites of primarily horses and other large mammals including cattle. It is a permanently fully winged fly, not shedding its wings on finding its host, as in some other Hippoboscidae. With its wings retained, it may thus fly away from its host to deposit its larvae. They are good fliers.
Wing length 6.0–8.5 millimetres (0.24–0.33 in). Generally pale reddish brown with yellow spots on the indistinctly segmented abdomen. They have one pair of sub-triangular wings and the wing veins are crowded together towards the anterior border.
The characteristic feature of these flies is that they move sidewards and they feed preferably between the hind legs and on the perineum region. The New Forest fly lays larvae singly in late instar (stage III). They rapidly pupate over one hour and exhibit varying duration as pupae, depending on temperature.
The primary distribution is in Europe and parts of Asia and Africa. It has been introduced to other locations, though in some cases latter eradicated by modern... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sierra Nevada National Park | 🇪🇸 Spain | |
| 2 | Pyrénées National Park | 🇫🇷 France | |
| 3 | Cévennes National Park | 🇫🇷 France | |
| 4 | Sierra de Guadarrama National Park | 🇪🇸 Spain |
With luck
About 10% of wildlife watchers report a New Forest Fly sighting in Pyrénées National Park on a given day, based on 14 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 576th most-seen of the 1277 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.
April and August–November
In those months about 10% of wildlife watchers report a New Forest Fly in Pyrénées National Park on a given day, against under 5% in May–July and December–March, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most New Forest Fly sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
Among the best
Of the 4 parks where we can rate New Forest Fly sightings, Pyrénées National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Sierra Nevada National Park (Spain, about 10%).
Same order: Diptera
The closest relatives of the New Forest Fly that you can see in Pyrénées National Park (order Diptera, Flies) are Common Drone Fly (about 10%), Tapered Drone Fly (about 10%) and Beech Gall Midge (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the New Forest Fly is recorded against all the insects logged in Pyrénées National Park (14 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.
