What is the significance of the way the birds are depicted in Section 7's introduction?

Woolf describes birds circling energetically, save a single bird which is perched on a branch apart from the others. The reader should infer from this that Woolf is suggesting that while some of the characters have reached a point in their lives where they can accomplish what they set out for themselves, there is at least one (Rhoda, Neville, or the two of them together) who are still paralyzed and cannot act. It is most appropriate to liken the solitary bird to Rhoda, as she has been the most paralyzed throughout the novel, whereas Neville remains functional, just not to the degree that Louis, Susan, Jinny, and Bernard appear to be.