Sounds like chirping to me! It really scared me the first time I heard it, too. One of my boars, Arthur, did it the second or third day I had him, and has never done it again, but one of my sows, Ava (fitting bird name!), does it quite regularly. She's still fairly young and tends to do it when she's really, really excited or there's something new that takes her interest.
Could definitely be the new cage that triggered it! It's weird how some do it but others don't.