Craesus septentrionalis
In 3 days ~10% in a week ~30%
Craesus septentrionalis, the flat-legged tenthred or birch sawfly, is a species of insect in the order Hymenoptera, the suborder Symphyta and the family Tenthredinidae. It was first described by Carl Linnaeus in 1758. The adult sawflies are black and brown with transparent wings and the larvae are yellowish-green and resemble caterpillars. The larvae feed on the leaves of various species of deciduous tree. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 2 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Birmingham | 🇬🇧 United Kingdom | |
| 2 | Helsinki | 🇫🇮 Finland | |
| 3 | Paris | 🇫🇷 France | |
| 4 | Saint Petersburg | 🇷🇺 Russia |
With luck
About 10% of wildlife watchers report a Hazel Sawfly sighting in Bavarian Forest National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 727th most-seen of the 1115 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.
September and October
In those months about 10% of wildlife watchers report a Hazel Sawfly in Bavarian Forest National Park on a given day, against under 5% in November to August, the lowest months.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Hazel Sawfly sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 parks where we can rate Hazel Sawfly sightings, Bavarian Forest National Park has the highest daily chance: about 10%. Next come Wadden Sea National Park (Germany, under 5%).
Same family: Tenthredinidae
The closest relatives of the Hazel Sawfly that you can see in Bavarian Forest National Park (family Tenthredinidae, Common Sawflies) are Yellow-Spotted Macrophya (about 10%), Turnip Sawfly (about 10%) and Figwort Sawfly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Hazel Sawfly is recorded against all the insects logged in Bavarian Forest National Park (7 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.
