Diagnosing high-pitched sound on start-up
 

Hi - I've been getting this sound when I start up my 2014 Fit. It lasts for a while, then goes away once I drive for a while. It's apparently not the drive belt system, as that has already been replaced. A mechanic I brought it to said he thinks it's the starter motor. Any other ideas?

Link to video file here:


Thanks!

Alternator bearing maybe? Or some kind of bearing?