What do the opening scenes of act 5 foreshadowing about the resolution of the tragedy of julius caesar

It is the scene where Cassius notices that the two eagles that have accompanied their army have now flown away.  In their place are ravens and crows to which the army sees as a bad omen.  This causes a break down in morale among the troops as Cassius and Brutus wonder about their fates.  Brutus swears that he will not be taken prisoner regardless of what happens today.