Eriocampa ovata
In 3 days ~10% in a week ~20%
Eriocampa ovata, known generally as the alder sawfly or woolly alder sawfly, is a species of common sawfly in the family Tenthredinidae. The larvae feed on the leaves of the common alder (Alnus glutinosa) and the grey alder (Alnus incana), sometimes causing defoliation.
The adult female is about 7 mm (0.3 in) long and mainly black, with the exception of the first two segments of the thorax, which are red, and the underside of the tips of the antennae, the inner side of the fore-tibia and the basal part of the hind femur, which are whitish. The head has numerous large puncture marks while the thorax has scattered smaller ones; the abdomen has faint transverse sculpturings. The wings are translucent with black veins. Adult males are unknown in North America, and rare in Europe, the females breeding by parthenogenesis.
The larvae grow to a length of 5 to 7.5 mm (0.2 to 0.3 in). They are white, apart from a brown mark on the head, and are covered with a glossy, white woolly secretion produced by epidermal glands. The alder sawfly is native to Europe, but has been accidentally introduced into North America, both the Atlantic and Pacific coasts... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Wadden Sea National Park | 🇩🇪 Germany | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | Birmingham | 🇬🇧 United Kingdom | |
| 3 | Manchester | 🇬🇧 United Kingdom | |
| 4 | Helsinki | 🇫🇮 Finland | |
| 5 | Warsaw | 🇵🇱 Poland | |
| 6 | Copenhagen | 🇩🇰 Denmark | |
| 7 | London | 🇬🇧 United Kingdom |
Rare
Under 5% of wildlife watchers report an Alder Sawfly sighting in Copenhagen on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 424th most-seen of the 476 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.
September
In that month about 10% of wildlife watchers report an Alder Sawfly in Copenhagen on a given day, against under 5% in October to August, the lowest months.
Between 3 and 6 pm
Across all the parks we cover, that three-hour window holds the most Alder Sawfly sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
6th of 7
Of the 7 cities where we can rate Alder Sawfly sightings, Copenhagen ranks 6th at under 5%. The best odds are in Liverpool (United Kingdom, about 10%), Birmingham (United Kingdom, about 10%) and Manchester (United Kingdom, under 5%).
GBIF citizen-science records
It is estimated from how often the Alder Sawfly is recorded against all the insects logged in Copenhagen (5 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.
