I’ve seen several Eastern bluebirds in my back yard lately. They flit from the old silver maple tree down to the open field and then back up and away. I lose track of them—and kick myself for not having installed my new bluebird nest box sooner.
I recently spoke with Dawn Hewitt, the editor of Bird Watcher’s Digest and Watching Backyard Birds, about maintaining bird feeders and baths. We also talked about the best times to install bird boxes.
“Today is the best day to put out a bird box,” Hewitt notes. “No matter what day it is. Put out a nest box any time—even if the birds don’t use it this season.”
Her answer surprised—and emboldened—me. Even though area bluebirds have likely already set up housekeeping elsewhere, I decided to go ahead and put up my nest box now. After all, some Eastern bluebirds will nest as late as September and they raise more than one clutch of eggs per season.
The Right Specifications
Want to attract a specific bird type? The overall nest box design—including size, shape, and entry hole diameter—makes all the difference. For instance, nest boxes for both Eastern and Western bluebirds should have an entry hole measuring one-and-one-half inches across.
Ideally, nest boxes should also feature a hinged door for cleaning, drainage holes and a sloped, overhanging roof. Unfortunately, I learned a little too late that nest box perches are actually unnecessary. Because perches can give predators a helping hand, I’ll be leaving them off of any future nest boxes.
When hoping to entice bluebirds, choosing the right location for the nest box is as important as nest box design. Ideally, each bluebird nest box should be mounted on a free-standing post about five feet off the ground. Bluebirds like wide open spaces with good visibility.
You can buy special posts and nest box mounting hardware kits, but I chose to create my own with materials I already had on hand.
I joined a small scrap wood platform to a steel can from my recycling bin. Then I drilled several long screws through the inside of the can in order to anchor it to my metal fence post.
Next, I inserted the post into the can and poured in some fast-setting concrete. After the concrete fully hardened, I was able to turn the post right-side-up and attach the nest box to the post’s wooden platform.
If I am lucky enough to attract a nesting pair of bluebirds, the last thing I want to do is frighten them off by getting too close with the lawn mower.
I used a string trimmer to remove a wide circle of grass and then prepared the ground for planting a low-growing ground cover. To mitigate weeds along the edge of my new planting bed, I added cardboard and topped with mulch.
Next, I dug out part of the center of the planting area and sank the post. I made sure the nest box was level and positioned at the right height.
Finally, I planted starts of goldmoss sedum, a forgiving perennial ground cover which should quickly fill in the area and eliminate the need to mow right by their post.
According to the North American Bluebird Society (NABS), if I successfully attract a nesting pair of bluebirds, I need to be willing to monitor them weekly. That’s because bluebirds frequently fend off predators, such as snakes and “outdoor” cats.
They also continually must compete with other creatures—rodents, insects, and even other birds—for their nesting spaces.
By learning about bluebirds’ life cycles and habits, I’ll know what to look for—and what to look out for—if they take up residence in the new box. In some cases, I may even be able to help prevent a nesting pair from abandoning the site.
Citizen science projects like NestWatch collect nest-monitoring data provided by the public.
Co-developed by the Cornell Lab of Ornithology and the Smithsonian Migratory Bird Center, NestWatch teaches participants how to safely track and report on the progress of nesting bluebirds and many other types.
I’d wanted to offer my own bluebird data to NestWatch. Now, however, it looks like I’ll be reporting on the house wrens that moved in one hour after my bluebird nest box was up. (They’re one of many critters that will commandeer a bluebird box.)
I’ll enjoy getting to know these new tenants, even as I hold out hope some bluebirds will give the box a try next spring.