blue tit and eggs gone (1 Viewer)

We have been enjoying watching a blue tit build her nest and lay about 10 eggs on our nestbox camera. She had just started to sit. However, after not viewing for 3 days, I was disappointed to find that the eggs and bird have gone. Not a trace. While viewing the empty nest, I observed a sparrow going in and turning the nest upside down and generally havinbg a good rummage.
What has happened to the blue tit and the eggs? Any suggestions?
Thanks

Could a mouse eat the eggs, I don't really know.

http://www.birdforum.net/showthread.php?t=33441

John.