When a quartet of nene showed up at work, a water bowl was put out for them. One of the nene, the leader of the group, stepped up to drink. One of the other birds looked on with interest, but was hesitant to join in (top photo).
The reason for that hesitancy became clear moments later when the first bird reached across and pecked the the other bird’s side. It didn’t appear to hurt, but a message was clearly being given. Soon after, the first bird finished drinking and then walked through the water bowl. It wasn’t like there was nowhere for it to go, but again, a message was being sent.
After the first bird moved on, the other bird took its opportunity to take a drink, muddy footprints and all.