Phylloscopus borealis
Silhouette: Jiekun He · PhyloPic
In 3 days ~10% in a week ~30%
The Arctic warbler (Phylloscopus borealis) is a widespread leaf warbler in birch or mixed birch forest near water throughout its breeding range in Fennoscandia and the northern Palearctic. It has established a foothold in North America, breeding in Alaska. This warbler is strongly migratory; the entire population winters in southeast Asia. It therefore has one of the longest migrations of any Old World insectivorous bird.
It traditionally included populations that breed in Kamchatka, the Kuril Islands and Japan, but genetic and vocal evidence strongly suggested these should be treated as separate species, and are all now considered distinct with the Kamchatka leaf warbler in Kamchatka, Hokkaido and the Kuril Islands, and the Japanese leaf warbler in Japan (except Hokkaido).
The nest is on the ground in a low shrub. Like most Old World warblers, this small passerine is insectivorous. This is a typical leaf warbler in appearance, greyish-green above and off-white below. Its single wing bar distinguishes it from most similar species except the greenish warbler, Phylloscopus trochiloides. It is larger than that species and has a heavier, dagger-like bill, with a dark tip to the lower mandible. Its song is a fast trill.
This species occurs as an autumn vagrant in western Europe and is annual on Great Britain. There were 225 confirmed arctic warbler sightings in Britain between 1958 and 2001. The genus name Phylloscopus is from Ancient Greek phullon, "leaf", and skopos, "seeker" (from skopeo, "to watch"). The specific borealis is from Latin and means "northern". Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Khao Luang National Park | 🇹🇭 Thailand | |
| 2 | Khao Sok National Park | 🇹🇭 Thailand | |
| 3 | Denali National Park | 🇺🇸 United States | |
| 4 | Way Kambas National Park | 🇮🇩 Indonesia | |
| 5 | Danum Valley Conservation Area | 🇲🇾 Malaysia | |
| 6 | Gobi Gurvansaikhan National Park | 🇲🇳 Mongolia | |
| 7 | Gunung Leuser National Park | 🇮🇩 Indonesia | |
| 8 | Taman Negara National Park | 🇲🇾 Malaysia | |
| 9 | Khao Yai National Park | 🇹🇭 Thailand | |
| 10 | Kerinci Seblat National Park | 🇮🇩 Indonesia | |
| 11 | Kaeng Krachan National Park | 🇹🇭 Thailand | |
| 12 | Cuc Phuong National Park | 🇻🇳 Vietnam | |
| 13 | Cat Tien National Park | 🇻🇳 Vietnam | |
| 14 | Taroko National Park | 🇹🇼 Taiwan | |
| 15 | Sepilok | 🇲🇾 Malaysia | |
| 16 | Bali Barat National Park | 🇮🇩 Indonesia | |
| 17 | Kinabalu Park | 🇲🇾 Malaysia | |
| 18 | Doi Inthanon National Park | 🇹🇭 Thailand |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Kaohsiung | 🇹🇼 Taiwan | |
| 2 | Singapore | 🇸🇬 Singapore | |
| 3 | Ningbo | 🇨🇳 China | |
| 4 | Manila | 🇵🇭 Philippines | |
| 5 | Taipei | 🇹🇼 Taiwan | |
| 6 | Kuala Lumpur | 🇲🇾 Malaysia | |
| 7 | Jinan | 🇨🇳 China | |
| 8 | Davao City | 🇵🇭 Philippines | |
| 9 | Taichung | 🇹🇼 Taiwan | |
| 10 | Novosibirsk | 🇷🇺 Russia |
Rare
Under 5% of wildlife watchers report an Arctic Warbler sighting in Seoul on a given day, based on 375 verified sightings from GBIF citizen-science data. It is the 76th most-seen of the 231 birds 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.
September
In that month about 30% of wildlife watchers report an Arctic Warbler in Seoul on a given day, against under 5% in June–August and November–April, the lowest months.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Arctic Warbler sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
13th of 31
Of the 31 cities where we can rate Arctic Warbler sightings, Seoul ranks 13th at under 5%. The best odds are in Kaohsiung (Taiwan, about 20%), Singapore (Singapore, about 20%) and Ningbo (China, about 20%).
GBIF citizen-science records
It is estimated from how often the Arctic Warbler is recorded against all the birds logged in Seoul (375 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.
