Building Houses for Wrens

Success!

Every spring I enjoy watching the diversity of bird species that visit my yard. For years I've been contemplating building some bird houses. Finally, this year I broke down and tried my hand at building birdhouses for House Wrens.

To start off the Cornell Lab of Ornithology website seemed the most helpful place to get some pointers on what features to have for a good bird house.

Visit the website by clicking here.

Using the information gathered there and elsewhere, I began designing my own house for Wrens. Below is the basic plan I ended up with. 

I used 1x6 and 1x8 cedar boards and coated deck screws. A note on lumber sizing... lumber almost never measures what it is described as (I can't remember the reason why). A 2x4 is almost never measuring 2" by 4". Therefore, the measurements of the cedar boards I used are accounted for in my diagram. The 8" boards appear as ones measured 7 1/2 (the 6" boards as 5 1/2").

I don't have a wood working shop or anything, so setting up and picking up is kind of a pain. The cutting of all the wood for the bird houses occurred on the same dry, sunny day as I made a new garden gate. I also employed my Kreg Jig with the assembly of the houses, not necessary- but makes for neater looking projects.

My birdhouse prototype

The original plan I found online didn't have a sloped roof as part of the house design. Water drainage seems to be pretty important, so I took the extra time to figure out what angles to cut the boards at to accommodate the sloped roof.

Really not that many pieces involved.

Some of the key features I'd like to reiterate are:

• a roof with an overlap on all sides to keep out moisture
• drainage holes in the floor to allow moisture to escape
• vent holes on the sides and near the roof to allow ventilation- birds get hot in the summer just like we do
•  1"-1 1/8 hole (I used a spade bit) that is large enough for the Wren, but too small for other birds
• NO PERCH 
• a floor that is raised up from the bottom edge (again to reduce moisture)
• some way to open the birdhouse up at the end of the year to clean it out for the next spring (I decided on small hinges and a strategically placed screw that keeps it closed)
• do not used pressure treated lumber
• use corrosion resistent fasteners 
• birds tend to be more attracted to natural looking building materials used in birdhouse making (as in made of wood and not painted)

The final form that my birdhouses took vs the prototype.

Why Wrens? One year I remembered we had a Wren that built a nest on a shelf inside our garage. For their size they are super noisy- in a good way. (Did you know that a Wren weighs about as much as two quarter coins?) Unfortunately, that year one of the nestlings fell directly onto a mouse trap that we had in the garage... and died. I've felt like I needed to make it up to them ever since. While conducting my web searches for Wren houses, I read somewhere that they are actually in decline in my area. Of course, I cannot fail to mention that Wrens are perfect for gardens, as their diet consists almost exclusively of INSECTS. Get to work Wrens!

They really do not use much lumber to make, so I made a handful!

I ended up making five all together. One I gifted to my dad, a fellow bird lover, for his birthday. The rest I positioned throughout my backyard.

About the positioning:

I was conscientious of not positioning them too close to one another as I figured it would generate unneeded competition or stress to the birds. One I mounted to our garage, one to my garden shed and two (one near the garden and one near our orchard) are mounted to metal chain-link fence posts (I think they poles were about 2" diameter. All my supplies including the baffle were purchased at Lowe's). The baffle is mentioned in the Cornell Lab of Ornithology link as a means of keeping out potential mischief makers... maybe chipmunks, maybe raccoon. They cost around $20, but I did not even want to mess around.

Also, for Wrens you do not want the houses too far from brush (they need supply sources from which to build their nests), but also not centered in the middle of a jungle either (this can freak them out, because they cannot spot predators as easily). So somewhere near a bushy area (and I feel like I read that the hole opening should face AWAY from the brush). The houses should not be placed too far off the ground, with 5-6 feet being fine I guess. The one I mounted to the garage is up higher and has Wrens living in it, but they found the ones closer to the ground quicker (as in a matter of days instead of weeks). So far, I know that three of the four houses are occupied! The one pictured below is located near one of my gardens and I can hear and see the Wrens coming and going... just singing, singing, singing... while I pull weeds and water plants. 

Example of one placed near my garden.