A downy woodpecker spent some nights in our birdhouse so we put some sawdust in there to make him more comfortable. Apparently he moved on, because a chickadee carried the sawdust out and built a nest in there. It's hard to be certain, because male and female chickadees look alike, but I think only one bird built the nest. We never did see two at the house at the same time. We didn't want to disturb the feathered architect so we stayed away from the house until the activity ceased and then I peeked in to find a beautiful nest constructed of moss from our old growth oak trees and lined with tiny, soft feathers.
I searched the web to find out about the nesting habits of chickadees and learned that the female builds the nest. Either she hasn't located a mate yet, because the house remains empty or it's a dummy nest. According to a web site, chickadees have been known to build dummy nests and abandon them. Yesterday, a chickadee visited the birdhouse and then left again.
Meanwhile, some chickadees in the area already have fledglings. We've seen a young one waiting on a nearby branch, chirping and fluttering its wings while the parents came to retrieve seeds from our feeders and deliver food to it.
We're hoping someone uses the birdhouse before the season is over.
Last year a titmouse pair built a nest in the birdhouse, but the 4 baby birds died in the nest. We don't know what happened to them - perhaps it was West Nile Virus.
By the way, that bag hanging off the side of the birdhouse is filled with nest building materials, none of which were used by the chickadees. We save cat fur and make it available to the birds in the front yard where our cats are not allowed to roam.
We recently purchased a birdhouse with a camera in it, but had to send it back because our wireless network connection caused interference with the image projected by the camera.