The Master of Suspense was famous for his scores, many of which were written by the composer Bernard Herrmann. Herrmann had provided the score for Hitchcock's previous film, Psycho, which included those unforgettable sawing, screeching, jagged violin bursts for the infamous shower scene.
For The Birds, Herrmann was relegated to the role of sound consultant; he didn't write a score. Instead, the soundtrack was handled by Oskar Sala, a German composer who used an early electronic synthesizer known as the trautonium.
Sala used the trautonium to create a synthesized soundtrack, including bird shrieks, wing flaps, and even the slamming of windows as people try to close out the winged invaders. Rather than music, there's an eerie electronic bird chorus. Does that make it scarier? Check out this version of the attic sequence dubbed with a full orchestral score and compare it to the original bird-only soundtrack, and see what you think.