What is the Amazon Fire HD doing?

Mrs. L.A.'s Amazon Fire HD periodically plays four escalating notes; like ‘Do-re-me-fa!’ Why does it do this?

Perhaps she has just received a FB message

She doesn’t have FB set up on it, and she never goes to FB.

Upper left hand corner. Click “Notifications.” She has a worthless message from Amazon about other stuff she can buy.

A little clarification: You have to keep your finger on the spot until the drop-down list appears, then slide your finger on it to display the whole list. Then press the spot that says “Clear all” to get rid of the list. It takes a little getting used to, just like any touchscreen device.

Mystery solved. She has new messages in Yahoo.