The music when the giant bird appears
How come it sounds so comical compared to the music during the other giant animal attacks?
"I'm in such bad shape, I'm wearing prescription underwear." Phyllis Diller 1917-2012
The creature's pace has a lot to do with the tempo. The composer wrote lively cues for agile things that could jump, stamp, lunge and change direction. In a soundtrack filled with "dark" and "heavy" cues and then some "romantic" material, one clownish and frantic piece puts everything else into perspective.
A giant bird attacking to a modified conga beat will shake up an audience.
Yes, Bernard Hermann saw it is comical and wrote the theme as such. Ray Harryhausen stated that the theme sounded "awkward", but was perfect for what he had visualized.
Incidentally, when both were looking a the rough cuts, Hermann joked that "Maybe I should use Turkey in the Straw as the theme!".
http://www.youtube.com/watch?v=2KBYIJA2uYs