Little Bird

A very small brown bird has built a nest in my geranium on my front porch (northern piedmont section of NC). Nest was built in July and she laid four eggs. She sat on those eggs for a good two weeks. They finally hatched four baby birds. The mama bird had been sitting on them to keep them warm, and I assume she'd been feeding them. But now I haven't seen her at all, and the babies huddle together and open their mouths for food when we get close. I'm afraid something happened to the mama, and the babies are going to starve. I will be so upset if that happens. The mama bird, and the babies, have an extremely distinctive thick horizontal white stripe across the head where the eyes are. The mama is very small and mostly brown, maybe a little lighter underneath. Very dark eyes. I believe she has a light-colored beak. The babies though look gray with a yellow-ish beak, but with that white stripe. Could someone please help identify this bird? I would be so upset if the babies don't make it.