Philereme transversata
In 3 days ~20% in a week ~30%
Philereme transversata, the dark umber, is a moth of the family Geometridae. It is found in much of the Palearctic realm. The wingspan is 29–37 mm. Variable in colour but generally very constant in markings, forewing with all the lines sharply angulated near the costa, the postmedian with an unusually long, double projection at the first radial. The ground-colour is bright ochreous brown or dark brown, the lines darker, the median band sometimes almost dissolved into lines but oftener more or less solid, at times quite blackish. — ab. hastedonensis Lamhill. is a melanotic form in which the brown ground-colour of the type form is in a large measure replaced by blackish. Described from Belgium, but occurs also near London. — japanaria Leech is lighter, with the median area of the forewing not or not appreciably darkened. Oiwake, Japan.
There is one generation per year with adults on wing from the beginning of June to August. The larvae feed on buckthorn (Rhamnus cathartica). The larvae can be found from the end of April to June. The caterpillar has two forms, one pale green and the other dark brown and cream. It overwinters as an egg. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 2 | Sierra de Guadarrama National Park | 🇪🇸 Spain |
With luck
About 10% of wildlife watchers report a Dark Umber sighting in London on a given day, based on 75 verified sightings from GBIF citizen-science data. It is the 428th most-seen of the 1504 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
June and July
In those months about 10% of wildlife watchers report a Dark Umber in London on a given day, against under 5% in August to May, the lowest months.
Between 10 pm and 1 am
Across all the parks we cover, that three-hour window holds the most Dark Umber sightings with a recorded time, and about 9 in 10 of them come between 6 pm and 6 am: it is mostly seen at night.
Yes
Of the 3 cities where we can rate Dark Umber sightings, London has the highest daily chance: about 10%. Next come Berlin (Germany, under 5%) and Vienna (Austria, under 5%).
GBIF citizen-science records
It is estimated from how often the Dark Umber is recorded against all the insects logged in London (75 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.
