Tragedy for the bluebirds.....

Tragedy for my bluebird friends today.  Just a few more days before the babies were due to leave their nest and an intruder came into the birdhouse.  I know it's part of nature, but still very upsetting.  I had a hard time watching the mommy and daddy bird come by time and time again to have a look inside their birdhouse to witness the sadness.... ):