Your mouth feels the crunch and warmth of meat and blood and bones. It is not pleasant. You accidentally ate a baby bird while you were attacking a different bird. You are too horrified with your actions to let the remains out of your mouth. Seeing your damage would be far too much to your currently frail being. You are also far too attached to the thing in your mouth to simply ingest it. Instead, you rest your tired and stressed bear body on the ground and sleep, hoping nature will take care of the baby bird after its life, as it did little to take care of the baby bird during its life.
You tried to save the baby bird. You tried so hard that you accidentally killed it.