On warm sunny days in the fall and early winter, you may see Eastern Bluebirds investigating every nest box in the area. What are they doing? They are accomplising two purposes with the visit. The first is to identify suitable roosting spots to use when the cold weather arrives. The second is to catalog acceptable nesting sites for next nesting season.
Eastern Bluebird checking nest box for roosting & nesting purposes
This morning I saw an interesting situation in my back yard. A Downy Woodpecker has selected one of the bluebird nest boxes as its winter roosting site. The nest box has a layer of pine wood chips covering the floor. A Bluebird flew in the nest box to check it out and a few seconds later the Downy Woodpecker flew in to see what the bluebird was up to. Fortunately, they decided to part on friendly terms with the Bluebird leaving first followed by the Woodpecker.