Yes.

From Bet's web site:
"Some bluebird trail monitors wish to deter HOWR from using their boxes because of the havoc they can wreak, and this page provides advice on various approaches. However, BE ADVISED that the HOWR is a native bird and it is illegal to harm them in any way or to interfere with active nests."

I think the nest is considered "active" if there are eggs or young. Find more specific's here:

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

Thanks,

I guess what I really meant to ask is whether or not the wrens would pose a threat to any bluebirds that might try to reacquire the "territory". How long will they hang around? Are they as persistent as the &^%*^%&&&^#$$^'n HOSP's?

Yes, and yes.

Incredibly persistent, especially before egg incubation starts. They migrate, depends on where you are located. In CT they show up in April, not sure when they leave (not soon enough? :-)

They "used" to be boarder-line spring in my area (Atlanta) but unfortunately they are staying though July....at least.....for the last two years. I'd rather deal with HOSP any day than HOWR.

Wow,

I've hosted BB's and TS's for 5 years now, but this is my first season dealing with wrens. Had I known they were so problematic, I would have begun tearing the nest out as soon as I saw it was being built.

ONe final question...the wren is not exclusively a cavity nester, is it? Coulda sworn I had one outside my window here last year in a reedlike plant growing by the wife's fishpond.

I thought they were cavity nesters (only) but I could be wrong. Do you have Carolina Wrens? That could be the wren you saw nesting in the reedlike plant.

Carolina Wrens are not destructive like House Wrens. CAWR are cheerful and welcome guests at my home any time!
CAWR will nest in many odd places; a nestbox or shelf, a flowerpot, a fallen tree stump, an old boot, a clay pot, a bush, a motorcycle helmet, a hole in a stone wall or mudbank, nooks & crannies, mailboxes, an old hat, a coat pocket, ... surely I've missed a few?
Our local garden center had a decorative nestbox on a shelf over the cash register. A pair of Carolina Wrens popped in and out as needed to feed their young surprising many customers, including me!
BlueBars

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

Ron,
If your Wren nest has only twigs, you can remove it.The way I interpret the law, it is NOT an active nest because it has neither eggs nor young birds in it.I remove the twigs as soon as I see it and I am persistent.They finally give up and move on.
michelle

Thanks for all the responses. Have one BB family fledged already, and Two TS families currently with eggs - one in a NABS box, the other in a plastic gourd...tree swallows really do go out of their way to endear themselves to us, at least I see it that way. Haven't seen the wrens since I removed the nest...hoping a BB family will claim it within the second clutch window for me here in SE Ohio.