House wrens are only a threat to Bluebird eggs and new hatchlings until they are about 6 days old, after that the wren can no longer pick them up and throw them from the nest which is what a wren will do to baby birds. If you had almost fully grown babies killed in the nest it was probably due to House Sparrows, the wren maybe came afterwards and filled the house with sticks. If you have wrens in the area once the Bluebird lays the first egg you can install a wren guard, but you would need to watch closely to make sure the Blues accept it, some don't. A wren guard is made of cardboard and comes down off the front of the nestbox and down to conceal the hole of the box from the frontal view, sides can be added to prevent a wren on the top of the nestbox looking down over and stills seeing the hole. Info on this is on the sialis.org site. Also to prevent House Sparrow attacks you can add a sparrow spooker to the nestbox once the first egg is laid, it is to be taken down right after fledging. This info is also on the sialis site. Good luck! Donna

very carefully (with a wide spatula or putty knife) remove the nest from the box, put it in a little paper bag of some sort (plastic will draw moisture which isn't good) and store it somewhere dry. sometime in the future, it may come in handy if an active nest is plagued with ants or mites, etc. as for preventing wren activity, it's pretty much a lost cause (at least in my own experience) once a wren has found the nest box. you may be able to move the box to a different location where you have not yet seen or heard wrens. if the blues nest again, immediately after the first egg is laid, slap a wren guard up and you might have a better chance of a successful nesting. i am holding my breath...i have 4 eggs due to hatch next wednesday, my female absolutely refuses to accept a wren guard and i'm hearing wrens all over the place. ugh!

The magic halo works for the first week or so until they get used to it and brave enough to ignore it. My HOSP use it to swing on and land on the short perches I use. They also swing on it back and forth to get the seeds out of the feeder without having to actually land on the perches. It does seem to keep the numbers down as some are wary of it and it does seem to hinder them somewhat, but I have lots of HOSP and they will try anything.

Please don't let House Wrens nest. You are allowed to remove their dummy stick nests until they move on. House wrens are very aggresive little birds that like to poke holes in other nesting birds eggs like Bluebirds, Chickadees, Tree Swallows, etc. So most people like myself that provide homes for the birds I just named do not let house wrens nest in their yard because of this reason. Thanks.