I would remove the whole nest and let her start over. If she builds a nest on top of the nest it will be to high and starlings and bluejays might be able to reach in the box and grab a baby. Good luck with this nest! Karen

House sparrows and bluebirds are mortal enemies; sparrows will build their nests right on top of the bluebird nestlings and kill them in this way. Watch for Dad bluebird trying to defend the nest. There should not be 2 nests in one box! Read an article on this; will try to find the link and post for you.

Thank you Lisa. Now the parents took the mealworm and flew away, so I opened the box this morning. All babies are gone, evidently fledged. There is a half build new nest on top of the old one. I think that I will remove the old one, and keep the new one in there. I think that the new one was build by a different female, not the Mom.

Wow it seems like me and you have a lot of the same! It has been in the 90's and hot here and now it just got more humid. I have a single dad taking care of 4 fledged babies! I also have a cooper's hawk and my neighbor kept putting out seed. This coopers shows up every day terrorizing the birds. When I hear blue jays,black birds, killdeer, and swallows giving alarm calls I know it is around. Just today I scared it from the other yard...guess where it headed...straight towards the babies! It landed in a tree next to them and they were totally silent...looser left with empty talons! Let us know what happens!