Unusual sounds on startup/shutdown

For the past few months (since the weather has gotten colder), my 2006 Prius (with about 21,000 miles) has been making strange shrieking sounds when turning on and off. I've read some similar threads here pointing to the coolant transfer pump needing replacement, but I think mine is sounding a bit different to the "pump.wav" sound attached in other threads.

The file I've attached here is a recording I made with my phone after shutting down. Apologies for the sound quality, but hopefully you can hear the difference. Does this sound like the coolant transfer pump, or something else?

Thanks in advance for any advice you may have. This is my first post to priuschat, but I've been lurking here for a long time and find this a really helpful resource.