Aha! I'd never thought of this as something akin to burying bones, but it makes a lot of sense! Strange that this is occurring as autumn is coming on, almost like a wild animal might feel that it's time to start storing away some food for winter...

By the way, I'll bet she's not "feeding" the birds so much as LURING them to her--she's got four bluejay kills already notched on her belt and is always looking for more!