The following day, I had my husband take another photo and this time the nest had six eggs.
Here is the progression of the nest. The birds started building over the robin's nest.
Then the nest turned into a mass of dried grass, leaves, bits of cotton, and some feathers. The night after we took this image, we had a storm and the wind blew away most of the materials.
The birds had started to build again, but we could see the original robin's nest on our light fixture.
This is a horribly blurry image because we took one quick photo as to not upset the parents too badly. If you look hard, you can see two baby birds. One has his head on top of the other. One has his head on the egg on the right and then the sibling has his head over this guys body.
We're not sure why the birds think it is a good idea to nest by our front door. It has to be a stressful situation for the birds because the front door is a busy place. We need to do something to discourage the birds from building there. We don't want the babies stressed every time we have a visitor or the mail is delivered.