Parking Brake (?) Noises On Start-Up

Every time I start up my 07 Prius, I do this in order:
1. Brake peddle pushed in,
2. Push 'Start' button,
3. Release parking brake,
4. Shift into gear & go.

I'm pretty sure when I release the p. brake I get this really strange noise. Like a chirping (maybe 3-4 times), but kind of matches a sound when you shut down the car. I had the parking brake adjusted a while back and it when away, then it started up again, little by little, until it's very noticeable. I had the dealer look at it just before the warranty ran out, but of course it didn't (hardly) make the sound. Maybe just a 1/4 sec sound, just once and he didn't hear it go figure!

Anyone know what this could be? Maybe I should do a sound bite with my camera.. lol

 

I think it is, thanks!!