Xanthorhoe ferrugata
In 3 days ~10% in a week ~30%
Xanthorhoe ferrugata, the dark-barred twin-spot carpet, is a moth of the genus Xanthorhoe in the family Geometridae. It was first described by Carl Alexander Clerck in 1759 and has a Holarctic distribution. It is found in Europe and east to the Russian Far East, Siberia, Tibet and China, south to the Caucasus and Turkey. Also in North America (Alaska to Newfoundland and south to North Carolina and California).
The name-typical form of ferrugata as figured by Clerck and well described by Linné, has the median band reddish or purplish, the distal area very weakly marked (except the costal patch and two dark spots between the radials) often almost entirely white or whitish. An aberration, ab. unidentaria Haw. is a very common and very interesting aberration which has been proved, by my very extensive breeding experiments and those of Dr. Draudt, to be an almost perfect Mendelian "recessive". It differs in having the median band black, not reddish. — ab. coarctata Prout has the median band greatly narrowed, only 1–2 mm. in width; the rest of the markings often in part obsolete. - bilbainensis Fuchs, from Bilbao, said to be a local race, is described... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Pyrénées National Park | 🇫🇷 France | |
| 3 | Wadden Sea National Park | 🇩🇪 Germany | |
| 4 | Bavarian Forest National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Porto | 🇵🇹 Portugal | |
| 2 | Detroit | 🇺🇸 United States | |
| 3 | Helsinki | 🇫🇮 Finland | |
| 4 | Liverpool | 🇬🇧 United Kingdom | |
| 5 | Boston | 🇺🇸 United States | |
| 6 | Edmonton | 🇨🇦 Canada | |
| 7 | Montreal | 🇨🇦 Canada | |
| 8 | Berlin | 🇩🇪 Germany | |
| 9 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 10 | Toronto | 🇨🇦 Canada |
Rare
Under 5% of wildlife watchers report a Dark-Barred Twin-Spot Carpet sighting in Boston on a given day, based on 32 verified sightings from GBIF citizen-science data. It is the 350th most-seen of the 1200 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
May–June and August
In those months about 10% of wildlife watchers report a Dark-Barred Twin-Spot Carpet in Boston on a given day, against under 5% in July and September–April, the lowest months.
Between 9 pm and midnight
Across all the parks we cover, that three-hour window holds the most Dark-Barred Twin-Spot Carpet sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.
5th of 12
Of the 12 cities where we can rate Dark-Barred Twin-Spot Carpet sightings, Boston ranks 5th at under 5%. The best odds are in Porto (Portugal, about 10%), Detroit (United States, about 10%) and Helsinki (Finland, about 10%).
GBIF citizen-science records
It is estimated from how often the Dark-Barred Twin-Spot Carpet is recorded against all the insects logged in Boston (32 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.
