Thanks guys. I was able to resolve the issue after reading your posts. The mouse did not have power settings as Antman suggested. However, when I sent to the Device Manager to find out the model of the built in Bluetooth card for FZ21Z, I noticed a Bluetooth power setting. Within the properties of the Dell Wireless 350 Bluetooth Module under the Power Management tab I found a setting that states "Allow the computer to turn off this device to save power." I unchecked it and the sound is gone. Basically, I had it backwards. The mouse was not going into power saver mode. Instead, the Bluetooth card was.
Thanks again.