Helophilus hybridus
In 3 days ~10% in a week ~20%
Helophilus hybridus is a hoverfly. It is a Palearctic species. For terms see Morphology of Diptera Wing length 8·5-11·25 mm. Femorae 3 top 1/4 or less yellow. Tibiae 3 pale on basal 1/4 or less. Males tergite 2 large yellow spotsreach the hind margin over their full width. The larva is illustrated by Hartley (1961). See references for determination
Palearctic Fennoscandia South to North France. Ireland East through North Europe and Central Europe (including the Alps) East into Russia and on through the Russian Far East and Siberia to the Pacific coast. Mongolia. Nearctic from Alaska to Nova Scotia and South to Utah.
Habitat: wetlands non-eutrophic pools in fen, poor fen, deciduous woodland and dune slacks, cutover valley bog, fen carr, taiga. Flowers visited include white umbellifers, Calluna vulgaris, Cirsium, Convolvulus, Crataegus, Echium, Euphorbia, Limonium, Lycopus, Mentha aquatica, Menyanthes, Narthecium, Parnassia palustris, Plantago, Pulicaria, Rosa, Rubus, Salix repens, Salix, Senecio, Sorbus, Succisa, Taraxacum, Valeriana.
The flight period is early May to early September. External images Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Riding Mountain National Park | 🇨🇦 Canada | |
| 2 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Anchorage | 🇺🇸 United States | |
| 2 | Edmonton | 🇨🇦 Canada | |
| 3 | Warsaw | 🇵🇱 Poland | |
| 4 | Birmingham | 🇬🇧 United Kingdom | |
| 5 | Manchester | 🇬🇧 United Kingdom | |
| 6 | Leeds | 🇬🇧 United Kingdom | |
| 7 | Helsinki | 🇫🇮 Finland | |
| 8 | Yekaterinburg | 🇷🇺 Russia | |
| 9 | London | 🇬🇧 United Kingdom | |
| 10 | Calgary | 🇨🇦 Canada |
Rare
Under 5% of wildlife watchers report a Woolly-Tailed Marsh Fly sighting in Wadden Sea National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 630th most-seen of the 818 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.
June and August
In those months about 10% of wildlife watchers report a Woolly-Tailed Marsh Fly in Wadden Sea National Park on a given day, against under 5% in July and September–May, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Woolly-Tailed Marsh Fly sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Woolly-Tailed Marsh Fly sightings, Wadden Sea National Park ranks 2nd at under 5%. The best odds are in Riding Mountain National Park (Canada, about 10%).
Same genus: Helophilus
The closest relatives of the Woolly-Tailed Marsh Fly that you can see in Wadden Sea National Park (genus Helophilus, Marsh Flies) are Sun Fly (about 10%) and Trivittate Marsh Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Woolly-Tailed Marsh Fly is recorded against all the insects logged in Wadden Sea National Park (6 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.
