February 9, 2021 Last Sunday morning, I went to Wajiro estuary in Hakata Bay. I was lucky to see some Oystercatchers (Miya kodori). A rather rare transient in this area. Common Shelducks (Tsukushigamo) were also there. Like their name suggests, they are common. They forage in shallow water by upending and head-dipping, but mostly by moving their bills back and forth through the water (scything), or by dabbling and digging on mudflats. I observed a few of them feeding in a style I have never seen before. They were stamping their feet rapidly, apparently to bring up prey to the surface of the mud. Other ducks do this on land to cause earthworms to come out of the ground. Perhaps it mimics the vibration of the rising tides, to bring up the small mollusks and other invertebrates that feed in shallow water.
As it was rather cloudy, I rode the bike back to where I had parked the car (no parking around Wajiro) at Tataragawa, about 7 kilometers away. When I arrived, the sun had started coming out from behind the clouds. I noticed the same small group of Black-faced Spoonbills I had photographed the weekend before (previous post) and took a short video.
They afternoon of the same day. Some images taken at Homan river near my home. A Pale Thrush (Shirohara), Common Kingfisher (Kawasemi), and Rufous Turle Dove (Kijibato) taken during the golden hour.
Thanks for visiting! Be safe everyone.
MOSTLY BIRDS 
Wow, that is strange behavior. Probably would be rare for an individual to discover this technique by itself, as opposed to the entire species having the trait. If you catch another one doing it next time, that would be a good indicator.
Nice pic of the turtle dove.
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Yes. It would be hard to pinpoint how this behavior was acquired. Self-learned behavior by individual birds is rare. I did see another Shelduck using the same stamping technique on the same day. One wonders if other Shelduck populations in other parts of Japan or other countries use this technique. Could it be “learned” from other populations during migration?
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