I just really love birds.

Loving the theme is a very good reason to play a game :) As long as you enjoy it, don't feel pressured to change!

Based on your changes, it seems you're looking for extra complexity and length. I don't know what other games you like, but I'd suggest Terraforming Mars as having similar gameplay with some of the changes you've house ruled. It's also got a bunch of expansions so you could adjust as you see fit.