In "The Birds," how do the BBC radio announcements create suspense as the story progresses?

At first, Nat and his wife derive some comfort from the announcements over the wireless, as these announcements inform him and his wife about what is going on. The wireless broadcasts also provide some relief that perhaps the authorities will take care of the problem of the birds, and the calmness of the announcer's voice quiets Nat's fear to some extent. The author writes about the radio announcer, "Nat had the impression that this man,...

At first, Nat and his wife derive some comfort from the announcements over the wireless, as these announcements inform him and his wife about what is going on. The wireless broadcasts also provide some relief that perhaps the authorities will take care of the problem of the birds, and the calmness of the announcer's voice quiets Nat's fear to some extent. The author writes about the radio announcer, "Nat had the impression that this man, in particular, treated the whole business as he would an elaborate joke." The announcer at first seems to regard the birds as a silly nuisance rather than as a serious problem.

Nat relies on the wireless to give him directions about what to do, and the broadcasts steady his nerves. However, the wireless announcer then says that there will be no more broadcasts at night, and although Nat eagerly awaits the promised 7 a.m. broadcast, the wireless does not receive any service in the morning. His radio can only receive foreign broadcasts, as the BBC is making no broadcasts. There is literally radio silence coming from London, which adds to the suspense of the story because it suggests that London has been decimated by birds.