Found baby starling bird in the parking lot. Thought he was about to die b/c he wasn’t moving much and was breathing heavily. put him in a box and was planning on taking him to a rehab center. He then seemed to perk up and hop around normal so I figured he was okay just exhausted.I put him back outside but by the window so I could keep an eye on him.I wanted him to get back with his parents he was at the fledging stage. A cat ran by and I just couldn’t leave him out there anymore to get eaten by a cat.I took him home and contacted a rehaber for info. I purchased baby bird formula and meal worms. We fed him the formula and drops of water to hydrate him for the first night and in the morning he was doing PERFECTLY. So yesterday we went on to meal worms, crushing their heads first so they didn’t bite. He took them down with no problem and was starting to show signs that he would soon learn to fly.This morning went in to feed him and he was dead. I’m so upset how could this happen?