Osmia bicornis
In 3 days ~20% in a week ~40%
Osmia bicornis (synonym Osmia rufa) is a species of mason bee, and is known as the red mason bee due to its covering of dense gingery hair. It is a solitary bee that nests in holes or stems and is polylectic, meaning it forages pollen from various different flowering plants. These bees can be seen aggregating together and nests in preexisting hollows, choosing not to excavate their own. These bees are not aggressive; they will only sting if handled very roughly and are safe to be closely observed by children. Females only mate once, usually with closely related males. Further, females can determine the sex ratio of their offspring based on their body size, where larger females will invest more in diploid females eggs than small bees. These bees also have trichromatic colour vision and are important pollinators in agriculture.
This species is part of the order Hymenoptera, which consists of bees, wasps, ants, and sawflies, and a member of the family Megachilidae, which mostly consists of solitary bees, and is among 11 species of Osmia identified in Britain. O. bicornis is the current scientific name for this bee, although it was formerly known as O. rufa... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 2 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 3 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Birmingham | 🇬🇧 United Kingdom | |
| 2 | Warsaw | 🇵🇱 Poland | |
| 3 | Liverpool | 🇬🇧 United Kingdom | |
| 4 | London | 🇬🇧 United Kingdom | |
| 5 | Manchester | 🇬🇧 United Kingdom | |
| 6 | Berlin | 🇩🇪 Germany | |
| 7 | Helsinki | 🇫🇮 Finland | |
| 8 | Hamburg | 🇩🇪 Germany | |
| 9 | Copenhagen | 🇩🇰 Denmark | |
| 10 | Cologne | 🇩🇪 Germany |
With luck
About 10% of wildlife watchers report a Red Mason Bee sighting in Snowdonia National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 336th most-seen of the 387 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
April
In that month about 20% of wildlife watchers report a Red Mason Bee in Snowdonia National Park on a given day, against under 5% in June to March, the lowest months. That is one of Snowdonia National Park's driest months, with about 95 mm of rain against 240 mm in December.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Red Mason Bee sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 3 parks where we can rate Red Mason Bee sightings, Snowdonia National Park ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Bavarian Forest National Park (Germany, about 10%).
Same order: Hymenoptera
The closest relatives of the Red Mason Bee that you can see in Snowdonia National Park (order Hymenoptera, Ants, Bees, Wasps, and Sawflies) are Common Carder Bumble Bee (about 20%), Red-Tailed Bumble Bee (about 20%) and Oak Marble Gall Wasp (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Red Mason Bee is recorded against all the insects logged in Snowdonia National Park (5 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.
