Just a small note - I live in Phoenix and over the winter there are a huge number of birds who make it their mission to bathe in my rock-waterfall. I would go out and my pool would have several feathers in it, and a weird gross scum was formed in my skimmer from all the filth.
I decided to get some bird tape (metallic shimmering tape you attach loosely so it flaps and shimmers over the area you want to keep bird free) and it actually worked extremely well. I have it so it flops around in the wind over my waterfall and I haven't seen any birds in my waterfall since. Supposedly the noise of the tape and the shimmering/movement keep the birds away.
So if anyone has a similar issue I can definitely recommend the stuff at least if you can attach it in a strategic place to keep them away - may not work for a "whole pool" issue