I need help right now, I found a baby bird and it's night time.?

I found it sitting on the ground in my garage. There is a nest right outside the door which has a blue egg in it. (It's august though so I'm not sure if that egg is just a dud.) The bird does have a lot of feathers and I don't think it's injured. I got it up onto a styrofoam box with towels around it and put it near the door so the mother could have a better chance of seeing it. I was at the other end of the garage for about an hour and I didn't see or hear any other birds. Should I feed it something? Do mothers feed at night? Should I wait until morning and call some rehabilitating wildlife center? (Couldn't find a number for this, I'm in Vermont.)