Two Bluebird Eggs

I was begining to think the Bluebirds had abandoned their nest since I haven't seen them recently so I was very surprised to find two tiny blue eggs in the nest when I checked it late Saturday. I will check the nest again on Monday since Bluebirds usually lay 4-5 eggs. During egg laying, the female leaves the eggs unattended and only begins incubating after the last egg is laid.