A coastal duck with a white body, a green-black head and a brown band across its chest.
Both sexes have a conspicuous white body and brown chest band. In the breeding season, the male's bill-base knob becomes larger.
Common shelducks can roam around familiar waters before settling elsewhere. Birds tracked in the eastern German Wadden Sea often visited several places rather than flying directly to their next sedentary area. One travelled 165 kilometres north to Denmark’s Nissum Fjord and returned to its previous area eight days later.
A study published online in 2023 analysed nine birds tagged during the 2011–2013 breeding seasons. Days classified as exploratory accounted for 6–39% of each bird’s tracking period, with tidal flats frequently visited. Among seven birds tracked through flightless moult, exploratory movements increased during the preceding 30 days. Their lives combined stays in restricted areas with periods of wider roaming.
An extinction-risk assessment has not been added yet.
Fukuoka’s 2024 account reports declines at Sone tidal flat and Hakata Bay after increases during the 1970s–1990s, while numbers at the Ariake Sea increased from the 2010s. The prefecture’s 2011 account suggested that nearby reclamation might affect changes at Sone and Wajiro tidal flats. Retaining broad feeding and resting flats is a conservation priority for these regional winter visitors.