When my husband began to water his large hanging staghorn fern, a bird flew up, protesting loudly! I don't know who was more startled, the human or the bird. It flew to the back fence, where we could see it was a mourning dove.
Investigation showed the nest, with its two white eggs. The pair lays only 2, maybe 2 more later in the summer. The sphagnum moss was practically enough as is, nestwise, but they did bring in a few wisps of dry grass.
We went upstairs and saw that it took the bird about 15 minutes to work its way back to the nest, flying across the garden to the other fence first, then making the leap, or flight, back. So we have been watching. The basket is wide enough that there is room for the nest and some watering can action without sogging up the nest, if we can do it without scaring the birds too much. They take turns on the nest. My husband noticed them changing today. It took a very long time for the partner to decide it was safe to go to the nest, and then the exchange was very fast. My husband found himself anthropomorphically thinking "Don't they want to get acquainted a bit when changing the guard?"
I'm afraid we can't tell Mom bird from Dad bird, but bird it is. The eggs hatch in about 2 weeks, and it has been over a week since our discovery, so... (I'll let you know when it happens.)