I love birds too, and DH and I are very much into birdwatching. We participate in Project Feederwatch for Cornell and have been counting and observing birds in our yard for years.

We have had many clutches of bluebirds fledge from two boxes on our property. Unfortunately, some of the pairs have taken to attacking our back windows, including our master bedroom ones. They poop all over the windows and siding and wake us up every day. Some years are much worse than others. This year started out bad, and my DH finally got fed up enough that he disabled both nestboxes by opening them wide so the birds would not nest in them. I felt really bad about that, but we do live on acres of woods surrounded by more acres of woods, so I am sure they will find a natural cavity to nest in. But not one where we get to see the feeding and fledging as we can from one of our boxes. Sigh...nature....

P.S. Aggie, I agree with others -- I think your birdie is a House Finch.