Xestia triangulum
In 3 days ~10% in a week ~20%
The double square-spot (Xestia triangulum) is a moth of the family Noctuidae. It is distributed through most of Europe except the Mediterranean islands and northernmost Fennoscandia. In the East, the species ranges East across the Palearctic to Siberia and in the South-East to the Black Sea and in Iran. It rises to a height of about 2,000 metres (6,600 ft) in the Alps.
This species has pale brown forewings marked with two distinctive black marks. Despite the common name, only one of these is square, the other being roughly triangular. The hindwings are similar in colour to the forewings. It is very similar to Xestia ditrapezium.
Differences: Xestia ditrapezium Front wing on average narrower (or longer). Ground colour of the forewings usually darker (red to violet-brown) and colour of the rear wing a shade lighter. Hindwings are significantly lighter than the forewings. Collar without contrasts, almost monochrome.
Xestia triangulum Forewings average wider (or shorter). Ground colour of the forewings of usually lighter (ochre to tawny or grayish brown) colour of the hindwings usually slightly darker grey. Hindwings about as light as the front wings. Lower part of the neck collar grey, separated by a light line from the dark upper.
Technical description and variation: The wingspan is 36–46 mm (1.4–1.8 in). Forewing grey brown, with a rufous tinge: a small blotch at base, a preapical costal spot, and the cell prominently black brown; hindwing fuscous.
The moth flies at night in June and July in the British Isles. It is attracted to light and sugar and to flowers such as wood sage. The larva is ochreous brown, black speckled; the lines pale; a row of oblique dark subdorsal bars. It is polyphagous, feeding on a wide variety of plants including birch, blackthorn, bramble, dock, hawthorn, raspberry and sallow. The species overwinters as a larva.
Inhabits preferably forest edges, slopes covered with shrubs, heaths and gardens and parkland. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Cairngorms National Park | 🇬🇧 United Kingdom | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Liverpool | 🇬🇧 United Kingdom | |
| 2 | Manchester | 🇬🇧 United Kingdom | |
| 3 | Helsinki | 🇫🇮 Finland | |
| 4 | London | 🇬🇧 United Kingdom | |
| 5 | Kyiv | 🇺🇦 Ukraine | |
| 6 | Birmingham | 🇬🇧 United Kingdom | |
| 7 | Berlin | 🇩🇪 Germany | |
| 8 | Moscow | 🇷🇺 Russia |
Rare
Under 5% of wildlife watchers report a Double Square-Spot sighting in Berlin on a given day, based on 7 verified sightings from GBIF citizen-science data. It is the 801st most-seen of the 1065 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.
July
In that month about 10% of wildlife watchers report a Double Square-Spot in Berlin on a given day, against under 5% in August to June, the lowest months. That is one of Berlin's wettest months, with about 80 mm of rain against 30 mm in April.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Double Square-Spot sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
7th of 8
Of the 8 cities where we can rate Double Square-Spot sightings, Berlin ranks 7th at under 5%. The best odds are in Liverpool (United Kingdom, about 20%), Manchester (United Kingdom, about 10%) and Helsinki (Finland, about 10%).
GBIF citizen-science records
It is estimated from how often the Double Square-Spot is recorded against all the insects logged in Berlin (7 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.
