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

The BBC radio announcements create suspense because they decrease in frequency over the course of the story. The day after the birds first attack, for example, the BBC airs an announcement from the Home Office which informs people how to protect themselves. This reassures people like Nat and creates a sense of national unity. A further announcement is made later in the day which, again, makes people feel as though the government is being pro-active and trying to help.

Suddenly, however, the radio announcements cease without any warning. This is suggestive of two things: firstly, that something major has happened in London, the capital city, and, secondly, that the government is unable to provide an effective solution against the birds. As Du Maurier never reveals why the radio announcements stop, the reader is left in a state of uncertainty and this is very effective in creating suspense.