So this was interesting. Upon arriving at a location where I was to conduct a prescribed burn, several Bluebirds gathered around us, one landing on a nearby post, another on the truck mirror. As we were unloading equipment, they continued to hang out, flying from the post to a nearby nest box, then back to the post, calling frequently. I noticed the nest box was open, so I walked over and closed the door. Within minutes, the birds were going in the nest box and no longer flying to the post. I saw several other nest boxes nearby so I went and closed them as well with birds investigating them soon afterwards. Now I don't ascribe human abilities to animals, but clearly the bird was trying to get my attention because it seems to have figured out I was capable of helping, whether it had observed humans closing nest boxes in the past or what I don't know.
Since these birds are monitored during the breeding season by humans, they have likely observed us manipulating various parts of the nest boxes. That leads me to believe that it's not the first time these birds have nested in the area.