What is an example of simile in the novel, Under Fire?

Example of Simile:

No sound comes from the long couches except when some one coughs, or that of the pages of a book turned over at long and regular intervals, or the undertone of question and quiet answer between neighbors, or now and again the crescendo disturbance of a daring crow, escaped to the balcony from those flocks that seem threaded across the immense transparency like chaplets of black pearls.