I took it to a bird rehabilitator, and she told me what to do if I ever rescued another fledgling or nestling.  She had a special syringe that goes all the way down the throat, to feed directly into the stomach...it bypasses the windpipe.

Next time I found a bird, I just grabbed a shoebox, grabbed a towel, placed the bird on the towel and put it in the shoebox, and raced off to a wildlife rehabilitation center.  They were actually surpised that I knew what to do, as I guess most people make the same mistakes (holding them, trying to feed them, etc.)

Ruth