Musca autumnalis
In 3 days ~10% in a week ~30%
Musca autumnalis, the face fly or autumn housefly, is a pest of cattle and horses. The face fly is similar to the closely related housefly but is slightly larger, averaging about 7–8 mm long and grey in colour with four dark stripes on the thorax, with a grey-black patterned abdomen. Like many true flies, in the males, the eyes almost touch when viewed from above.
Musca autumnalis is widespread throughout most of Europe, Central Asia, northern India, Pakistan, China and some parts of North Africa. It was introduced into North America around the 1940s and has now occupies a territory from southern Canada into most temperate parts of the United States. It was also introduced to St. Helena Island in the South Atlantic.
Adult face flies will emerge from winter hibernation around March to early April. During the daytime, they feed on manure juices and plant sugars. On cattle and horses, they feed on secretions around the eyes, mouth and nostrils. The adult flies will also feed on the hosts' blood through wounds such as horse-fly bites. A larger proportion of face flies on the host will be females, as they have a higher need for protein... Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Face Fly sighting in London on a given day, based on 38 verified sightings from GBIF citizen-science data. It is the 559th most-seen of the 1504 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.
March–April and July–September
In those months about 10% of wildlife watchers report a Face Fly in London on a given day, against under 5% in May–June and October–February, the lowest months.
Yes
Of the 2 cities where we can rate Face Fly sightings, London has the highest daily chance: under 5%. Next come Essen (Germany, under 5%).
GBIF citizen-science records
It is estimated from how often the Face Fly is recorded against all the insects logged in London (38 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.
