There was a single Australasian Grebe swimming on a local pond. I thought this bird was just swimming, looking for food, when it climbed on top a mess of leaves and other plant matter. The bird then commenced poking at the leaves, before it sat on top of the pile. In looking at the photographs later there may have been an egg in the middle of the pile, partly covered by some leaves. The grebe did not stay on the nest long before it once again started swimming but on the closer side of the nest. I am not sure why it went back to the nest as it did not stay there long and none of the other birds were heading for the nest, although a juvenile Eurasian Coot was also swimming in that part of the pond.