Are you sure the completed nest has no eggs?Chickadees will cover their eggs when leaving the nest.DON'T poke around the nest to check.I always use a 1 1/8" reducer on all my houses that Chickadees choose.I have never had any abandon the nest,But I always install it after I am sure eggs have been laid.If if were me I would keep a eye on them for a few days.When you are sure eggs have been layed ,install the reducer.As far as the nest that has just been started,If the blues do take it over,a least the Chickadees can still use the empty box you have.I have never used a reducer during nest building.

Great photos - so interesting to see the one carrying out the woodchips, and the two cooperating. So neat to think of them making a home from a woodpecker's home. A question - I have had a chickadee (or a pair)flying in and out of a nestbox. I am thrilled at the possibility of their nesting there. After a week or so I checked the nestbox, and there was a nest! But now for the last week or so I haven't seen them nearby at all. I checked the nest yesterday, and no eggs. Could I have "jinxed" the nest by checking on it? I thought it was okay to peek in. I didn't touch anything, just opened the door, looked, and shut it. I would hate to think I scared them off somehow after they did all that work building. Any thoughts?

My observation is that in the egg-laying phase, the female roosts in the box to lay an egg in the early morning, then she leaves the box for the day. This is what the 'book' also says. However, there is a difference between what the 'book' says and what I have observed this year as to the start of incubation. The 'book' says that she starts incubating, i.e. she stays in the box for the day with short interruptions (and roosts in the box at night) when she has laid her penultimate egg. In other words, the 'book' says that she will lay another egg the next morning after she stays in the box for the first incubation day. What I have observed this year is that she did not lay another egg after she stayed in the box for the first incubation day. (She is incubating 7 eggs now) As to fur blankets, what I have observed are fur blankets of up to perhaps half an inch thick. Last year bird was somewhat diligent in covering the eggs when she left the box. This year bird mostly leaves the eggs uncovered when she leaves the box. This different nesting behavior is perhaps another indication that it is not the same bird that nests in the box.

It's been a while, but here is an update! Wrens did appear the day our chickadee nest was emptied, so we are guessing they were responsible. The mother chickadee spent one more night on her empty nest before abandoning it. We ended up putting duct tape over the hole so the wrens couldn't use it and boy did that make them mad! I've learned that we may have played a role in the chickadees demise. Three years ago chickadees nested in our yard, but the next year wrens did. We kept removing the sticks, but they promptly replaced them. The wrens are hard workers, I'll give them that. Finally we left the wrens alone and they completed a nest, etc. From what I've read, once you let wrens nest in your yard, they become very territorial of it and it is almost impossible for chickadees to have a successful nest there. Last year we put up two very low bluebird boxes and the wrens built dummy nests in them. Also we had put a few wood chips in our nest box. I think the reason chickadees like a box with wood chips is that it mimics an old woodpecker's nest. If woodpeckers successfully nested in a spot, there is probably a higher chance it will be successful for chickadees. So maybe we gave them a false sense of security. Well, we live and learn. Every once in a while now I will be outside and I'll hear two chickadees calling and they will fly close to me and flit all around and it makes me really happy. We now have flickers nesting in an old woodpecker hole in our birch tree. Starlings recently fledged from that hole, and there have been a few brawls, but I've got my fingers crossed. A few times I have gone out and banged pans to frighten the starlings away and it seems to work! Good luck with your nest boxes Donna! Thanks for the pep talk, it was nice to talk with someone who could relate! Annie