Biston strataria
In 3 days ~20% in a week ~40%
Biston strataria, the oak beauty, is a moth of the family Geometridae. It is native to Europe, the Balkan countries and the Black Sea region as far as Asia Minor and the Caucasus. The species was first described by Johann Siegfried Hufnagel in 1767. B. strataria is found in a variety of habitats, but is mostly found in woodlands where it rests on the bark of trees, camouflaged by its mottled black and grey wings. The male has feather-like antennae while those of the female are more thread-like. The moth has a wingspan of 40 to 56 mm (1.6 to 2.2 in).
The larvae are mainly brown with three lumps near the end of the abdomen. They have evolved to resemble sticks which helps protect them from predators. The larvae feed on many species of trees, but the most commonly used host plants are oaks.
The oak beauty has white forewings with two irregular broad brown bands along each wing. The first band is short, located near the base of the wing, and surrounded with a black border. The second band is located near the outer margin with a black border surrounding the inner edge. Between these two bands is a white space sprinkled with black dots as well as a crescent-shaped black... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Sierra de Guadarrama National Park | 🇪🇸 Spain | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany | |
| 5 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | Porto | 🇵🇹 Portugal | |
| 3 | London | 🇬🇧 United Kingdom | |
| 4 | Birmingham | 🇬🇧 United Kingdom | |
| 5 | Helsinki | 🇫🇮 Finland | |
| 6 | Copenhagen | 🇩🇰 Denmark | |
| 7 | Prague | 🇨🇿 Czechia | |
| 8 | Berlin | 🇩🇪 Germany | |
| 9 | Vienna | 🇦🇹 Austria | |
| 10 | Moscow | 🇷🇺 Russia |
With luck
About 10% of wildlife watchers report a European Oak Beauty sighting in Porto on a given day, based on 24 verified sightings from GBIF citizen-science data. It is the 211th most-seen of the 498 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.
February
In that month about 20% of wildlife watchers report a European Oak Beauty in Porto on a given day, against under 5% in April to November, the lowest months.
Between 9 pm and midnight
Across all the parks we cover, that three-hour window holds the most European Oak Beauty sightings with a recorded time, and about half of them come between 6 pm and 6 am: it is seen both by day and at night.
Among the best
Of the 10 cities where we can rate European Oak Beauty sightings, Porto ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Liverpool (United Kingdom, about 10%).
Same family: Geometridae
The closest relatives of the European Oak Beauty that you can see in Porto (family Geometridae, Geometer Moths) are Double-Striped Pug (about 20%), Vestal (about 20%) and Pale Oak Beauty (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the European Oak Beauty is recorded against all the insects logged in Porto (24 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.
