Hi Chico: The baby bird might have had a underline illness and that is why it died..Did the officer check the bird out for puntcure wounds or anyother signs? Could also have been attacked by a cat? I always checked out fledglings to make sure they seemed healthy and thriving...meaning i checked under the wings, wings, skinniness, keel, etc.
I understand where you are coming from. It is hard seeing a fledgling and not wanting to help it, however sometimes helping it, can cause it more stress. It is best to leave it alone, observe from a distance and only intervene when needed. Like I said, you have to let nature takes it's course. Most survive, some don't, as hard as that is too say.
I know there is a lady in Rockwood runs S.O.A.R