I enjoyed this a lot, and I listened to it without reading your comments, and I thought, It sounds like I'm floating over a beautiful scene or a city, because of the lush sounds and the wonderful flute lines. Then I read that it's about birds, so, well done! I think the only problem is the mix is a little distorted.
I noticed this on your description:
"The harmonies can be a little "muddy" in some parts, but this was an early composition."
That's pretty much the only criticism I'd have on this piece. The melody's really nice and flows well.
Sometimes the passing tones in the bass (especially chromatic descents) clash with the melody, since oftentimes it seems to be a seventh chord with the seventh in the bass and the tonic in the soprano.