Sad News

Today, about 4:30am, there was a loud commotion on the side of the house. Birds squawking like crazy for about 15-20 minutes. I didn't think much of it when I went to work.
But when I got home from work, I went to check on the robin's nest. I realized that the nest with the babies was destroyed. I found feathers in the backyard, and even a tiny foot. The babies are dead.
I'm not sure what it was... a crow, raccoon, rat, or something else... but whatever it was the babies are gone. Momma has been hanging around the back yard, looking like she's at a loss as to what to next. I'm sad for her.