This is the most astonishing behaviour I have ever seen in something non-human. One swan attacked the other, it's mate, while it was eating - head underwater to feed on the water-plants. It basically grabbed it's mate by the neck, pulled it toward the cygnet, then went off to feed. It was saying "I'm hungry - YOU look after the kid!"
"I don't think I can reach that!"
"Mum, you're embarrassing me!"
"I wonder what's over this way?"
"Can I swim now?"
"Is the water still warm?"
"I love swimming!"
"I'm staying right here until you eat your dinner!"
"OK, I'll eat my greens, Mum."