Spring cleaning and what I found

Yesterday was almost warm. I decided to empty the old bird nests out of the bird houses. This way the bird houses will be clean and ready for new birds to move in and build new nests.
Remember when we did this last year?

I found old nests in 8 of the houses. Some were made of moss and some of sticks.One nest still had three little eggs in it.

I wonder what bird lays little pink spotted eggs.

I wonder why they didn't hatch?