Taken from a report on Mount Moon in a FireRed Let's Play Thread by Red Chocobo:
Report: ...I'd like to make an aside and say this: Mount Moon has made me hate Zubat with no end. Zubat Zubat Zubat. Endless swarms of damnnable Zubat. I was breathing Zubat with every breath. I couldn't move my arm without hitting a dozen Zubat into about a hundred other Zubat, causing them to all get pissed off and start divebombing me... (it goes on and it continues about 3/4 down this page).