Once the tide had covered Pasir Puteh, we moved to Sejingkat ashponds (#2 on the map), where we observed a large mixed flock of Eurasian and Eastern Curlews.
The birds were extremely wary and eventually took flight.
This was the reason - a hunting Osprey. Being exclusively a fish-feeder, it was not remotely interested in the curlews, but they weren't to know that!
This flock of Eurasian Curlews seems to be following the Osprey!
Curlews are much easier to identify in flight than 'on the deck'. From below, the pure white underwing coverts of Eurasian make them stand out clearly from the barred, darker Easterns.
Even from a distance!
While from above, their white rump and back give them away instantly.