I'm sorry, I don't know what your mystery birds are. Could they be TRES (tree swallows)???? What type nesting material are they using?

I can tell you that in MY experience, "yes" a bluebird will kick a dee out of a box. If my dees start building and are showing definite signs of nesting in a box I add a 1 1/4th or 1 1/8 inch hole reducer to keep the bluebirds out of the box the dees have claimed. I have 6 baby dees right now!

I am thinking the dark gray with a white belly, fluffy head, might be a phoebe? Do a google image search on Eastern Phoebe to see some pics (assuming they are in your geographic range?) Their belly is actually a very pale yellow.
The bluebirds might very well evict the chickadees. You can install a hole reducer to keep the blues out. See Bet's web page on hole reducers. And you can add another nestbox for the blues; hurry!
BlueBars

Here is a link that might be useful: http://www.sialis.org/holereducer.htm

thanks for the quick responses. An Eastern Phoebe is exactly the bird - even the nests shown on the web resemble what they are starting to build. So any opinions on what we should do? The trailer is going to be moved real soon........

I thought about putting another box out for the blues - I will get one out soon.

Oh my, can't you give that trailer a flat tire or something and make it stay a while longer?
I guess if were my decision, I would remove the nest before they lay eggs; probably against the law, but in this case maybe better for them to build elsewhere, poor things.
I wish you could send them to my back yard!
BlueBars

The owners are in no hurry to pickup the trailer - but it is a definite eye sore for us - and we kind of want it gone asap. However - I didn't expect any birds to make a nest out of it.... and it's not like I can ask them to please build their nest elsewhere. If they can pick it up this week - then hopefully the birds will find somewhere else.

Nesting is just a few weeks, you are so lucky to have these little guys nesting with you. Please reconsider moving it if you can. If not be sure there are not any eggs in it and see if you can find another safe location for it nearby. They may not accept you moving it but it's worth a try. Whatever you do dont let that trailer go with a nest and eggs in it.

Phoebes are very cool birds and Michigan is a very cool state! You could take the nesting material out and build a nesting shelf like the ones a Robin would use, they like to nest under a bridge, eave or gutter. Look it up on google. pretty easy to make and maybe that will be incentive for them to stay with you.
Good Luck Cathy

Thanks for the responses. When I got home yesterday - my wife said the birds were back and forth from under the trailer..... but I decided to go ahead and remove the nesting material - as the nest was just in the beginning stage. Although it looked like they did put a little work into it - some dried mud, and moss. But not so far along that they cant relocate. I also setup not far from the trailer a ledge type house to see if will entice them - but not to confident it will. I hated to remove them from their spot - but it was probably best.

Well I thought I would update this post. After I removed the nesting material from under the storage trailer - the birds moved on - and I didn't see until last week. And again they started to build under the storage trailer. So I again removed the nesting material. This time I built a couple nesting boxes - and hung them under the overhang of our home - on on each side of the house. I placed the nesting material on one. To our surprise the next day - she found the box, and started building. She worked on it all weekend - and it looks as though it is complete. A real pretty nest - a nice cup of mud lined w/ moss. I plan on taking a pic today if I get a chance.

We are however disappointed - The blues never showed up, and now the box that they have used the last two years has been claimed by a Wren. I seen him putting some sticks in it the other day. We have two other boxes w/ chickadees nesting.... but not the same w/o the blues.

No way! Phoebes in a nestbox!?! At least we thought they were phoebes ... could they be Flycatchers!?! OMG That would be really special! See pics & more info about them on Bet's web page.
AND chickadees ... you are very fortunate! I would be honored to have either birds nesting with me! (The house wrens, I could live without.)
Bluebars

Here is a link that might be useful: http://www.sialis.org/gcfl.htm

Sorry.... It was not an actual box - I built a ledge type bird house. I guess I am used to calling them nest boxes.....

Still no Blues..... We can only hope for maybe the second nesting - but I haven't seen or heard any. They nested here the last two years - I'm thinking maybe one of the pair was killed, or they found a new home.

But here is the pic of our newcomers this year. I'm glad they changed their mind on where they wanted the nest......

Thanks for the update. So glad you were able to accommodate them. Great pics! What a beautiful nest. And Mrs. Phoebe looks so comfy cozy in there. Please keep us posted on their progress.
Here is Bet's page on Phoebe's with pics:

Here is a link that might be useful: http://www.sialis.org/nestsphoebe.htm

I would not let the wrens nest there if I wanted bcch or blue birds. Two people have lost dees to wrens and a couple lost tutis and bhnu too. I would put up a wren guard on those occupied boxes. I would try to keep them busy until the dees fledge'
Cathy

Great photos, thanks for the update.

I agree with Cathy about adding a wren guard the the nest box hosting the chickadees.

I thought about the Wren guards - but have never put one on before. Both chickadee boxes have eggs and they are incubating them - would this dicourage them at all? The wrens have been around now for a couple weeks - and have not bothered them - so I assume - maybe they'll be OK? It seems like the Wrens arrived early this year - maybe the early spell of warm weather we had.

I've been following this thread and am so glad the Phoebe got to nest in a safe place. I had one which built on top of a downspout elbow, just under the deck; she had a couple of broods per year until two seasons ago, when she disappeared before eggs were laid. For the past couple of days I've seen a Phoebe on the deck railing, calling "fee-bee" over and over. Perhaps a new male looking for a mate?

I had the deck re-done so the old, many-times-reused nest is gone. But I'm hoping to build a platform with a small ledge around the edge and mount it just under the deck. I'd love to know what size (dimensions) you decided to make yours; don't want to make mine too small.

On another note: after the original Phoebe didn't return to the nest on the downspout, some enterprising Carolina Wrens came along and "renovated" the existing nest. They had four babies, all of which I found all on the cement walkway under the deck a couple of days after they hatched. House Wrens had thrown them out. Two were dead. I put the nest in a small can, built up the nesting materials in the front to prevent the remaining babies from falling out again -- also laid foam pads down below, just in case. Next day, the surviving two were on the ground again. Thankfully they lived, and with the help of a rehabber, I raised them successfully. Oh, those House Wrens!!!

P.S. - I just looked up Eastern Phoebe in my Stokes bird book. It says that at least 25% of Phoebe nests are parasitized by cowbirds. So watch that nest carefully for an intruder egg.

Thanks for the reply. I was wondering - if I remove the nesting material after the birds fledge - or leave it. I am used to the Bluebirds - of cleaning out the box, but wasn't sure on other birds. So it sounds like we should leave this nest for reuse?

We live in a primary wooded lot - and the house wrens take up residence - I hear/see at least three. I was really surprised when we first purchased the property - the only non-wooded area was a half an acre wetland - which we put the bluebird house on - and the blues immediately took up residence - for two years. Except this year - which is disappointing - because now we actually live on the property.

Does anyone know if House Sparrows stay clear of wooded areas? We can hear them w/ their annoying chirping at our neighbors - but they never enter our property - which is surrounded by trees. Just curious.

Thanks again for the replies.

I'm wondering if anybody knows if Carolina Wrens will reuse a nest? Last year I had a nest in a flower pot near my back door. The wrens were there about a month and after the fledglings left we would see them occassionally in the yard for the remainder of the summer. Yesterday I saw one coming back and forth to the old nest with new pine needles, almost like he was refreshing it to use again this season. It is around the same time as last year that they nested there....is it possible they will return and use the same nest?

oddiep Well I guess the CAWR answered the question for us. They are back.

Hosps do not stay clear of wooded areas if there are woods around where people live. They don't prefer woods but they have wings and they fly to nesting or food even if it is quite far out. They usually stay away from really open pastures and fields too prefering to stay up by buildings but I have had them kill tres and eabls way out in the pasture. Wrens are a problem where ever they are too but I don't have trouble with them way out in the open.
Cathy

Oh No!!! I still wasn't sure if the wrens were back so yesterday I decided to peak in the nest. I think it was mother bird and I startled her and she flew off!! Now I'm afraid they won't be back....no eggs in the nest but this was around the time last year!....Hoping she forgot she saw me peaking and returns. : (