Tortrix viridana
In 3 days ~20% in a week ~40%
The green oak tortrix, Tortrix viridana, also known as the European oak leafroller and the green oak moth, is a distinctive green moth whose larvae feed on tree leaves, especially oak. The head, forebody and front wings are green, the hind wings lightly greyish. The wingspan is 18-24 millimetres.
An infestation of the larvae can defoliate an oak tree. The adult female lays its eggs next to leaf buds, which the larvae consume when they emerge. As the larvae grow bigger they eat larger leaves, and then roll themselves up in a full-sized leaf to pupate.
Larvae occur from April to June; adults are on wing in June and July. The Ichneumon wasp Dirophanes invisor is a parasitoid which specializes on T. viridana. They are commonly found in many parts of Britain. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as common. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Cévennes National Park | 🇫🇷 France | |
| 2 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 3 | Wadden Sea National Park | 🇩🇪 Germany | |
| 4 | Sierra de Guadarrama National Park | 🇪🇸 Spain |
With luck
About 10% of wildlife watchers report a Green Oak Tortrix sighting in Stockholm on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 85th most-seen of the 202 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.
June
In that month about 20% of wildlife watchers report a Green Oak Tortrix in Stockholm on a given day, against under 5% in July to May, the lowest months. That is one of Stockholm's wettest months, with about 80 mm of rain against 35 mm in April.
Between 6 and 9 am
Across all the parks we cover, that three-hour window holds the most Green Oak Tortrix sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
Among the best
Of the 19 cities where we can rate Green Oak Tortrix sightings, Stockholm ranks 4th at about 10%, level with the leaders once rounded. The best odds are in London (United Kingdom, about 10%), Sofia (Bulgaria, about 10%) and Liverpool (United Kingdom, about 10%).
Same order: Lepidoptera
The closest relatives of the Green Oak Tortrix that you can see in Stockholm (order Lepidoptera, Butterflies and Moths) are Green-Veined White (about 20%), European Peacock Butterfly (about 10%) and Red Admiral (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Green Oak Tortrix is recorded against all the insects logged in Stockholm (10 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.
