Merodon equestris
In 3 days ~10% in a week ~20%
Merodon equestris (Narcissus bulb fly, greater bulb fly, large bulb fly, large Narcissus fly) is a Holarctic species of hoverfly (Family Syrphidae). Like many other hoverflies it displays a colouration pattern similar to a stinging insect (a bumblebee in this case) as an evolutionary defense mechanism. Other syrphid bee mimics are Mallota, Arctophila, Criorhina, Pocota and Brachypalpus. Merodon species are distinguished from these by the very strong hind femora, which bear a large triangular projection on the underside near the tip. It flies in low vegetation while the other bumblebee mimics prefer higher vegetation layers.
A stout fly with a small head (10–14 mm in length). The tergites are black, without the dust spots or blue-purple sheen of other Merodon species. The thorax and abdomen are hidden by dense, long, erect hairs of variable colouration. Tibia 3 of the male has 2 spurs at the apex.
Males have eyes clearly touching at the front, while in females these are separated by a (yellow haired) antenna like structure at the front. In the... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 3 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 4 | Acadia National Park | 🇺🇸 United States | |
| 5 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 6 | Wadden Sea National Park | 🇩🇪 Germany | |
| 7 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Birmingham | 🇬🇧 United Kingdom | |
| 2 | London | 🇬🇧 United Kingdom | |
| 3 | Liverpool | 🇬🇧 United Kingdom | |
| 4 | Manchester | 🇬🇧 United Kingdom | |
| 5 | Portland | 🇺🇸 United States | |
| 6 | Copenhagen | 🇩🇰 Denmark | |
| 7 | Boston | 🇺🇸 United States | |
| 8 | Hamburg | 🇩🇪 Germany | |
| 9 | Leeds | 🇬🇧 United Kingdom | |
| 10 | Seattle | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Narcissus Bulb Fly sighting in San Francisco on a given day, based on 100 verified sightings from GBIF citizen-science data. It is the 158th most-seen of the 737 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April and May
In those months about 10% of wildlife watchers report a Narcissus Bulb Fly in San Francisco on a given day, against under 5% in June to March, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Narcissus Bulb 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.
38th of 42
Of the 42 cities where we can rate Narcissus Bulb Fly sightings, San Francisco ranks 38th at under 5%. The best odds are in Birmingham (United Kingdom, about 20%), London (United Kingdom, about 20%) and Liverpool (United Kingdom, about 20%).
Same family: Syrphidae
The closest relatives of the Narcissus Bulb Fly that you can see in San Francisco (family Syrphidae, Hover Flies) are Oblique Streaktail (about 10%), Eurasian Drone Fly (about 10%) and Thick-Legged Hover Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Narcissus Bulb Fly is recorded against all the insects logged in San Francisco (100 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.
