[Gpdd] BEHAVIOUR: Tweeting

[mtjaffe at verizon.net]

Wondering if anyone's piggie has done something similar? I let Lucky out of his cage last night -- he did his usual laps around the room and then came to rest with a startled look on his face-- sniffing the air and then started to tweet-- much like a bird.  This was definitely not a wheet but a tweet.  His ears made a strange motion back and forth motion while he did it, and he almost looked like he was in a trance and/or scared (I couldn't tell for sure).  He would stop for a moment and move his mouth like he was slowing extra saliva (like an untrained singer) and then start again.  This continued on for what seemed like a long time, but was probably just over 5 minutes.  After he stopped he was behaving oddly -- wouldn't take his favorite treats.
At first I was amused, but as it went on I was worried.But maybe I'm making too much of it because I'm paranoid about his health.  He has been through a stone surgery in the last 3 weeks and came through it well, but still isn't quite himself and is on antibiotics.
Any thoughts or similar experiences?  At first I thought it was the mysterious "singing" that some GPDD'ers have heard but he seemed so unlike his usual self that I found it worrisome.  Within the half hour he seemed back to normal but somewhat subdued.

Lucky's slave