The Watarase Yusuichi (Watarase Retarding Basin) in Tochigi and Ibaraki Prefectures, north of Tokyo, is Japan’s largest inland wetland and a critical site for rare raptors and migratory waterbirds. Listed as a Ramsar wetland, this vast floodplain retaining basin provides habitat for over 250 recorded bird species throughout the year.
Star Birds
Eastern Marsh Harrier
Watarase is one of Japan’s premier sites for the Eastern Marsh Harrier. Multiple individuals quarter the reed beds throughout the year, with breeding confirmed regularly. Observing a male’s aerial food pass to the female is one of the great raptor spectacles of Japanese birdwatching.
Other Raptors
White-tailed Eagle, Rough-legged Buzzard, Grey-faced Buzzard, and Peregrine Falcon are regular winter visitors. Black Kite patrols the water margins year-round. Rare visitors have included Eastern Imperial Eagle.
Waterbirds
Great White Egret, Grey Heron, Night Heron, and Black-crowned Night Heron breed in the mixed heronry. Bean Goose, Tundra Swan, and thousands of ducks winter on open water.
Best Time to Visit
- Winter (Nov-Mar): Peak for raptors, geese, and swans
- Spring (Apr-May): Harriers actively displaying; migratory passerines
- Summer (Jun-Aug): Heronry active; reed and marsh specialists
Travel Tips
The basin is accessible from Watarase-Onsen Station on the Ryomo Line from Omiya or Takasaki. Cycling around the perimeter embankments is an excellent way to cover the extensive wetland. A telescope is essential for raptor watching over the reed beds. Early morning visits give the best light for photography.
