There are about fifty gadwalls and several Eurasian coots in the river.
The coots collect algae at this time of year. The gadwalls attach to the coots. When coots are collecting algae, the gadwall will take away the algae spilled by the coot, and sometimes the algae that the coot is holding.
The coot dived to collect algae.
A gadwall stole algae from the coot.
The next is a video of the sequence of actions.
The other scene is next.
A coot dived to collect algae.
A gadwall chases the coot that has taken algae.
The gadwall tries to steal algae from the coot.
The gadwall stole algae from the coot.
Next is a video of the sequence of actions.