These aggregate or nested nests, blow-ins from the bird world, went through an empty nest phase, prompting the question is a nest a nest if there is nothing in it? Is a house a house if it does not  house?
The bob-tailed snub-beaked white-breasted whistler, who wheezes something like an A, might be an interloper or a steadfast tenant, whose gravitas keeps the nests well -balanced.