Japan’s coastal tidal flats — higata — are among East Asia’s most important staging grounds for migratory shorebirds following the East Asian-Australasian Flyway. Vast intertidal mudflats in Isahaya Bay, Tokyo Bay’s surviving fragments, Fujimae in Nagoya and the Ariake Sea shoreline support millions of birds during spring and autumn migration, and some of the highest concentrations of rare and globally threatened shorebird species anywhere on the planet.
The East Asian-Australasian Flyway
Japan sits on one of the world’s great migratory bird corridors, connecting breeding grounds in Arctic Siberia and Alaska with wintering areas in Australia and New Zealand. Shorebirds flying this route include species that make non-stop trans-oceanic flights of over 10,000 kilometres, requiring productive staging areas to refuel. Japanese tidal flats provide critical foraging habitat at the northern end of these flights, particularly during May (northward) and August–September (southward) migration peaks.
Globally threatened species including the Spoon-billed Sandpiper, Far Eastern Curlew and Great Knot use Japanese tidal flats. The Spoon-billed Sandpiper — with its uniquely spatulate bill — is one of the world’s rarest birds, with a total population estimated below 400 individuals; Japanese tidal flats at Fujimae and elsewhere in Aichi Prefecture are among the few places in the world where encounters are possible.
Key Birdwatching Sites
Fujimae Tidal Flat, Nagoya (Aichi): One of Japan’s most celebrated shorebird sites, designated a Ramsar Wetland of International Importance in 2002. The tidal flat at the mouth of the Shonai River in Nagoya Port hosts 10,000+ shorebirds during peak migration. The adjacent Fujimae Wildlife Refuge Centre provides viewing platforms, scopes and volunteer guides on weekend mornings in May and September. Accessible by Nagoya Municipal Subway (Kinjo Futo Station) — a 20-minute walk from the station.
Yatsu Higata, Narashino (Chiba): A relatively small but highly productive urban tidal flat on Tokyo Bay, surrounded by residential development. The Yatsu Higata Nature Observation Centre provides year-round access to observation platforms overlooking the mudflat. Spring and autumn migration periods bring rare shorebirds that stop here on what is now one of Tokyo Bay’s last significant intertidal areas. Accessible by Keisei Tsudanuma Station.
Isahaya Bay and Ariake Sea, Kyushu: The Ariake Sea’s enormous tidal range (up to 6 metres) exposes extensive mudflats supporting huge concentrations of migrating and wintering shorebirds. The contested history of land reclamation at Isahaya Bay — where a major tidal barrage was constructed in 1997 — has made this region a focal point for debates about coastal ecosystem conservation in Japan. Remaining open flats near Arao City, Kumamoto, are accessible by rental car.
Lake Biwa’s Delta Areas and Biwako Marsh: While primarily a freshwater site, Biwa’s delta areas at Maibara and Hikone attract passage waders and wintering duck concentrations including rare species from Siberian breeding grounds.
What to Bring
A spotting scope (20–60x magnification) is essential for identifying small shorebirds on distant mudflats — binoculars alone are insufficient for species identification at most sites. A field guide specific to Japanese or East Asian shorebirds, waterproof footwear (some sites involve soft mudflat edges), and layers for variable coastal weather complete the kit. Photography requires a lens of at least 400mm equivalent for frame-filling images of small waders; 500–600mm is standard for serious flight shots.
Birdwatching Seasons
Spring passage (late April–late May) brings northbound shorebirds in fresh breeding plumage — the most spectacular condition. Autumn passage (July–September) has longer duration but birds are in duller eclipse plumage. Winter brings ducks, geese, divers and raptors to coastal and lake sites. Year-round residents include herons, egrets, kingfisher and Japanese cormorant visible at all tidal flat sites from platform viewing areas.