Eastern Bluebird: Nest Built

I previously mentioned a few days ago that, unlike last year (May 12, May 19, Jun 19, and Jul 29), the bluebirds were active around the bluebird box (Mar 29 and Mar 31)this spring. I finally took a minute to quickly look at the inside of the box. This photo shows what I found. I did not keep the box open for long, nor did I disturb the nest, but no eggs were observed.

As you can see in the photo below, I did not even need to open the box to see that a nest had been built - not the grass coming out of the box door.