The following lines are from the novel "To the Lighthouse" by Virginia Woolf:

"The window panes were blurred, the trees were blurred; the leaves were blurred in the breeze. The breeze came in faint puffs, then died away. The sun became brighter, and now a single bird chirped, and another answered, and another, and others, and the first bird sang out loud and clear, and another answered, and another, and others, and the air was filled with chirping and with the humming of bees and the whirring of wings."

Which of the following statements best describes the use of imagery in these lines?