So, originally I thought there were three. I'm happy to say I was mistaken, and at last check there were four, and they were all doing well! Here are some photos:
They are only about 6 days old (in the photos, 8 today), but have grown quite a bit. They have more feathers, but their eyes still aren't open. And are they ever hungry! Mamma spends her day finding food, and while she is searching they sit still with their little beaks open and waiting for a fresh worm.
I got a couple photos of mamma this time, but I didn't want to get too close, for fear that I would frighten her.