I was on the phone with my sisters this afternoon and I took the call outside because I hadn't looked at the plants today. The aphids are back in force on the lupin (sigh) and while I was looking at those, I noticed the ants. They're the same size as the ones that herd the aphids on the fruit trees but these ants were nowhere near those trees.
Even weirder, these ants looked like they were carrying smaller, dead ants and pieces of what looked like pieces of peanuts. And there were a ton of ants doing this. As I looked closer, I realized that the white things that looked like pieces of peanuts were eggs and the small, dead ants were alive. These ants were moving to a new nest under one of the plants. I traced their trail back to the starting point and it looks like their original nest is or was under the waterfall.
I've never seen ants do anything like this. Ian said that they might be splitting the nest in two and carrying new eggs, babies, and workers to the new nest. It was interesting to watch. Watching nature is cool.