Sphrageidus similis
In 3 days ~40% in a week ~60%
The yellow-tail, goldtail moth or swan moth (Sphrageidus similis) is a moth of the family Erebidae. The species was first described by Johann Kaspar Füssli in 1775, and has commonly been placed within the related genus Euproctis. It is distributed throughout Europe to the Urals, then east across the Palearctic to Siberia and south to India and Sri Lanka.
This species has a wingspan of 35–45 mm, the female usually noticeably larger than the male. All parts of the adults are pure white, apart from a bright yellow tip to the abdomen (larger in the female) and a small black or brown tornal mark on the forewing of the male.
White, and very like Euproctis chrysorrhoea, but more pure silky white, anal wool and hairs at the apex of the abdomen of the female golden yellow. Not rarely, especially in the male sex, color forms occur with small dark spots on the forewing: form "auriflua" has three spots at the inner angle, forming an oblique transverse row, and one spot in the basal area near the hindmargin; form "nyctea" has only one spot at the inner angle as well as one in the basal area like "auriflua"; form "trimaculata" is like "nyctea" but has another... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Snowdonia National Park | 🇬🇧 United Kingdom | |
| 2 | Białowieża National Park | 🇵🇱 Poland | |
| 3 | Wadden Sea National Park | 🇩🇪 Germany | |
| 4 | Pyrénées National Park | 🇫🇷 France | |
| 5 | Bavarian Forest National Park | 🇩🇪 Germany |
With luck
About 10% of wildlife watchers report a Swan Moth sighting in Białowieża National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 82nd most-seen of the 158 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 60%, if each day is a fresh chance.
April and June–July
In those months about 20% of wildlife watchers report a Swan Moth in Białowieża National Park on a given day, against under 5% in August to March, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Swan Moth sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
2nd of 5
Of the 5 parks where we can rate Swan Moth sightings, Białowieża National Park ranks 2nd at about 10%. The best odds are in Snowdonia National Park (United Kingdom, about 20%).
Same family: Erebidae
The closest relatives of the Swan Moth that you can see in Białowieża National Park (family Erebidae, Underwing, Tiger, Tussock, and Allied Moths) are Scarlet Tiger (about 20%), White Ermine (about 20%) and Garden Tiger (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Swan Moth is recorded against all the insects logged in Białowieża National Park (9 verified sightings from 2019 to 2026), 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.
