New Wren Houses Go Unused

[Luker]

Last winter I built nine wren houses from 3/4 inch cedar boards which are rough on one side and attached them 8 feet off the ground to trees in my one acre urban yard. I've included a picture of one. This summer all went unused. I know wrens were around, and one nested in a junky birdhouse instead of choosing mine.

I am wondering if my problem has to do with the entry hole. I glued a second piece of cedar, rough side out, at the entrance to prevent squirrels from reaching inside, and then drilled a 7/8 inch entry hole, sized to stop sparrows from nesting. Is the 1 1/2 hole depth too much for the wrens to navigate? Is the glue smell a problem for them? I thought about enlarging the front of the hole with a wood rasp if that would help.

[fishlkmich]

You need a 1 1/8" (minimum) hole for House Wrens and a 1 1/2" hole for Carolina Wrens.

Most birds cannot smell. Toxic products should not be used for obvious reasons.

House Wrens fill all of my bluebird boxes with sticks, until I plug the holes and make them move on. Once Wrens are established, they will be with you FOREVER! They (House Wrens) have a nasty habit of pecking the eggs of other birds, which is why I discourage them. If you do not have other native birds, Wrens would be a nice, but noisy, addition to your yard.

[Random]

I agree with fishlkmich that the hole is too small.

The wrens here are Carolina and they will pass through predator guards no problem. They also seem to strongly prefer to nest up against the house as an eastern phoebe will. Sort of using humans as a defense system. They also build nests in boxes then actually lay eggs in my door wreath (now a wall wreath due to this), garage, or eaves of my deck roof or in my pocket if I stand still too long. If your wrens are Carolina wrens I would suggest mounting a box close to the house as you can in a lower traffic area.

But different species of wrens differ in their behavior so knowing the species you have around will help.

and I also second no glue. Adorable house by the by!

[gnomenative]

I know that there are "standard" sizes for wren house holes. My own experience is that the birds don't measure.

I go with the size of a quarter- which is 1". I have also used the same cedar boards that you used and they have worked. I usually have more nesting in my houses after they have been out and seasoned a year, but that is not an exclusive statement. I made several for my parents and all were used the first year.

I would not use glue or any other adhesive or finish. Plain old cedar works great and weathers well.

Here is a picture of my son making an entrance hole in a wren house. They are our favorite after kestral houses!

[Equilibrium]

Hiya gnomenative!!! You've got a future wildlife gardeners there don't you! Excellent excellent excellent photo! Hiya Luker!!! I'd go with a larger entry hole. I found something for you that helped me since I had nest boxes for bluebirds but wanted to provide for house wrens too and it made a lot of sense once I started thinking about it, Bluebird Restoration Association of Wisconsin "Even less is the competition from House Wrens. First of all, if one places a nest box 100’+ away from short, dense, brushy vegetation, wrens usually do not build in those boxes and if they do so, build dummy nests. Secondly, wrens migrate back to WI even later than swallows. Since they do not even start nesting until mid-May, nearly 100% of nest-seeking bluebirds have selected boxes by then. Therefore, wrens are almost never a competitor in the 1st nesting cycle, but can become a major competitor in the 2nd and/or 3rd nesting cycles for bluebirds."