The camera stays inside the house, which is like a fortress besieged by invisible attackers. The predatory birds are kept off-screen as long as the walls, windows and doors are barricaded.
The effect produced by this soundtrack is one of:
The variations in the loudness of the screeching functions hand in hand with the effect of suspense: the crescendo and the banging sounds suggest that the birds’ intrusion into the house is only a matter of time.
