I'm pretty sure they are two separate pairs. I had two pairs last year nest in my yard. One was in a Bluebird box in the backyard, I would recommend putting a hole reducer on that box (that is what I did) to protect the m from other larger birds. Go to www.sialis.org for all the info you need on all cavity nesting birds. So much info
Cathy

Thanks Cathy. I do love the Sialis site. I have been using it for years. It really does provide so much terrific info. I don't really want to install a hole reducer because I actually did put the box out for the Blues. The Chickadees just claimed it as soon as it went up!! :o) I love the little Chickadees and don't mind at all if they use the box, but I want the Blues to be able to use it too.

My chickadees used our birdhouse and had 2 eggs in it when a wren went in, poked the eggs and started taking out the nesting material😪 soso weso we took theso we took the birdso we took the birdhouse down! will they make a nest elsewhere and continue laying their eggs? thanks