A bluebird dilemma

A few days ago I showed you a picture of our female bluebird sitting on her eggs. Today I checked on the nest again and she wasn't there, so I got to see the eggs. The nest is a little high up, so I have to stand on a step stool and I had to tilt the nest cup (its in an egg carton kind of cup) to take this picture.



As you can see, we do have bluebird eggs in there, five of them! There are also four other eggs, and I'm not sure what they are. House Sparrows are considered a pest and you're suppossed to dispose of house sparrow eggs and nests found in bluebird boxes. I don't think thats what they are though. It is probably more likely that they are Carolina Chickadee eggs. I'm not sure what to do with them though. It seems like this would create a problem for the baby bluebirds. I just sent an email to someone who runs a bluebird website, hopefully they'll have some advice.