She is under the moss at the top of the first picture - and then trying to get out of the box with the piece of hay in the second.
This is where Fantail seems bent on wrecking her nest. It seems there is a big bit of hay in it that she doesn't like. You can't really see her in the first image, but she is there - buried under the moss and hay. She grabs the hay stalk and makes for the exit - nearly dragging the whole nest with her!