This passage from Act II, Scene 4 of Macbeth occurs in a time lapse since the murder of Duncan. The old man and Ross speak of strange omens and how ambition is ruinous to men, unconsciously alluding to Macbeth's observance of his own "vaulting ambition" which has driven him to regicide.
The old man's reference to an owl parallels that of Lady Macbeth's earlier feelings of guilt as she imagines hearing an owl's shrieking, which she tells her husband in Scene 2 has caused her to halt in her intention to "....have done the deed. Didst thou not hear a noise?" (1.2.15) In addition to coinciding with Lady Macbeth's sense of guilt, the conversation between Ross and the old man about the bizarre occurrences indicates the upsetting of the natural order that the death of King Duncan has wrought because the Chain of Being, in which the Elizabethans firmly believed, has been disturbed. For, when the semi-divine king dies, the world order is greatly disturbed. Not only does this Chain of Being constitute the plot structure of Shakespeare's plays, but it affects the psychology of his characters and the fates that they confront.