When you speed up the second part, it does sound a bit like starlings, or some other bird. But the first part, the more eerie sounding part, I don't know of a bird that sounds that way -- but then, I'm no bird sound expert, by any stretch.
This reminds me of an LP record my dad got at an auction or thrift store a long long time ago, called "Symphony Of The Birds".
The guy who made the record took various bird songs (probably tape loops), layered them and pitch shifted them, and mixed them together, forming various 'movements'. Parts of it sounded very eerie. A record of 'musique concrete' using bird sounds, basically.
This YouTube is an excerpt from it. Sounds like the LP as I recall it, kind of eerie in places:
http://www.youtube.com/watch?v=7rKjOR-4964