Horornis diphone
Silhouette: Sheatherius · PhyloPic
In 3 days ~10% in a week ~20%
The Japanese bush warbler (Horornis diphone), known in Japanese as uguisu (鶯), is an Asian passerine bird more often heard than seen. Its distinctive breeding song can be heard throughout much of Japan from the start of spring.
The Japanese bush warbler is olive brown above and tending toward dusky colors below. It has pale eyebrows. It has a beak that curves up making it look like it is smiling. The bird is typically 15.5 centimetres (6.1 in) in length.
The Japanese bush warbler is a common year-round resident throughout Japan (except Hokkaidō) and the northern Philippines. In summer the Japanese bush warbler can also be found in Hokkaidō, Manchuria, Korea, and central China. In winter, the bush-warbler can also be found in southern China and Taiwan.
It was introduced to Oahu between 1929 and 1941 and has since spread throughout the main Hawaiian Islands. In summer, it ranges from low hills to high mountains, preferring bamboo thickets and black pine trees. In winter it seeks cover at lower elevations.
The propensity of the Japanese bush warbler to sing has led to the birds being kept as cage birds. Robert...
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Nikko National Park | 🇯🇵 Japan | |
| 2 | Hawaii Volcanoes National Park | 🇺🇸 United States | |
| 3 | Haleakala National Park | 🇺🇸 United States | |
| 4 | Kilauea Point National Wildlife Refuge | 🇺🇸 United States | |
| 5 | Taroko National Park | 🇹🇼 Taiwan |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Ueno Zoo | 🇯🇵 Japan | |
| 2 | Inokashira Park Zoo | 🇯🇵 Japan |
Rare
Under 5% of wildlife watchers report a Japanese Bush Warbler sighting in Kilauea Point National Wildlife Refuge on a given day, based on 23 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 25th most-seen of the 44 birds 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 Japanese Bush Warbler in Kilauea Point National Wildlife Refuge on a given day, against under 5% in August to June, the lowest months.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Japanese Bush Warbler sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 5
Of the 5 parks where we can rate Japanese Bush Warbler sightings, Kilauea Point National Wildlife Refuge ranks 4th at under 5%. The best odds are in Nikko National Park (Japan, about 70%), Hawaii Volcanoes National Park (United States, about 40%) and Haleakala National Park (United States, about 40%).
Same order: Passeriformes
The closest relatives of the Japanese Bush Warbler that you can see in Kilauea Point National Wildlife Refuge (order Passeriformes, Perching Birds) are Brazilian Cardinal (about 70%), Warbling White-eye (about 60%) and Northern Cardinal (about 50%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Japanese Bush Warbler is recorded against all the birds logged in Kilauea Point National Wildlife Refuge (23 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.
