Why are there raptures in the birds nest?

OK. SO maybe they are not exactly Raptors, but they kind of look like it, don't they. I didn't go to check on them over the weekend because it was miserable weather, wet and chilly. I didn't want to scare the mama bird off the nest, leaving the babies exposed. Today when I sent Jimmy over to take some snap shots of the birds for me, (I can't get over there thanks to the cast and crutches, update on the later) he iscovered one of the babies is gone. The runt of the group was pushed out of the nest and died. The nest wasn't big enough for them all and the mama bird was having trouble taking care of them all. I am worse than a kid. I couldn't believe that the mama did that. Jimmy had to sit there and remind me how nature works. I know it, but it always makes me sad. I then had to explain to Serenity, the 6 year old, why the mother did that. That was not a fun thing to explain. The next question I had to explain was the people are not like animals. So here are my little raptors. I think they look like the raptors in Jurassic Park, kind of.