Birdsnests in the Backyard

We have a lot of birds and nests in our new backyard. This photo is from the nest in the planter box hanging from the fence. This was a dove's nest, she hatched one or two babies, but today no one was home and we saw this egg left behind.

This nest was in a tree near the backdoor. It was also doves. She had two babies but they already grew up and flew away.

These next two photos are a nest that is near the playset. I haven't seen it occupied since before we moved in. I don't remember what kind of bird was there but it was smaller than a dove. I never noticed these eggs before so either I just missed them earlier (this nest is quite a bit higher than the others), or a bird has returned to use this nest again.