Thanks for the replies - so far the House Wren has not touched the surviving two Baby Blues - and momma and Papa are taking care of them. However - I can hear the Wrens all around, and I also am removing sticks from the other boxes around the property. I should have tried a Wren guard - however I have never put one on - so was worried about the Blues not taking too it. But if they nest again, I will for sure try it - after the first egg is laid. One a side note - we have a dead tree in our back yard - that a wood pecker bored a hole in, and must now have a nest in it. I saw her chasing the wren a way - but her nest is pretty high up. Also - we have a Phoebe nesting under our overhang - this is her second year. I went and checked her eggs out - and there was a Cowbird egg in it! We also had two robins nest near our house - both nests were robbed of their eggs - I'm thinking the crows got at them. Unfortunately no Chickadee nests in our boxes this year.. but probably best because of the Wrens..... seems like they arrived early this year. So did the humming birds.

go to the sialis.org website and try to determine how old the baby is. When was the last time you checked the box? Also post this over on the BlueBird forum for more help.

It's not impossible, but it is unlikely that little screeches might take a bluebird, especially during nesting season, when they have hungry owl mouths to feed. But screech owls mainly hunt at night, when blues are tucked away.

It has happened to us too! Very puzzling!