Osmia bicolor
In 3 days ~10% in a week ~20%
Osmia bicolor, the two-coloured mason-bee, is a Palearctic species of bee in the genus Osmia. It is outstanding amongst other megachilid bees in that it nests in empty snail shells. Osmia bicolor females are small bees, 12 mm in length, with a black head and thorax and an abdomen covered in bright ginger hair. In the males the ginger colour of the abdomen is less intense.
Osmia bicolor is found in Europe and western Asia from southern Great Britain in the west east to Turkestan, it is found as far north as southern Scandinavia and Finland, and south as far as Spain and Romania. It occurs in grasslands and open deciduous woodland over calcareous soils underlain by rocks such as limestone and chalk.
Osmia bicolor is univoltine in western Europe and is among the first bees to emerge in the spring, males can be seen as early as February, although the normal flight period is from April to July. The females emerge a few weeks after the males and are quickly mated. Compared to females the males have a very short life. Once mated the female O. bicolor seeks out the empty shells of snails, In Britain it has been recorded using the... Wikipedia →
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Red-Tailed Mason Bee sighting in Vienna on a given day, based on 12 verified sightings from GBIF citizen-science data. It is the 838th most-seen of the 1406 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
In that month about 10% of wildlife watchers report a Red-Tailed Mason Bee in Vienna on a given day, against under 5% in May to March, the lowest months.
3rd of 3
Of the 3 cities where we can rate Red-Tailed Mason Bee sightings, Vienna ranks 3rd at under 5%. The best odds are in Warsaw (Poland, about 10%) and Prague (Czechia, under 5%).
GBIF citizen-science records
It is estimated from how often the Red-Tailed Mason Bee is recorded against all the insects logged in Vienna (12 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.
