Dove Egg

Hi, I'm super new here and I'm so sorry if this isn't the place to post this thread. So we have a lot of doves that constantly come to our backyard and tonight I noticed that one had laid an egg on our window sill. The egg won't survive the night as there's no nest and the mother is nowhere in sight. The ledge it's sitting on is literally only a few centimeters wide and any gust of wind will knock it right off. Should I take it inside and try to keep it warm? I have absolutely 0 experience with birds let alone eggs/baby birds. I don't have an incubator or really any other heat source... I'm willing to do almost anything it takes to keep the baby alive. Or perhaps I should just leave it alone and let nature take it's course? Please, any help is much appreciated