Get Boxes Ready for Bluebirds
by Doug Reeves, assistant chief, DNR Wildlife Division
Do you want a good activity to get you thinking about spring? Then build a bluebird box or two and put it/them up in a good place. Do it now. It really is only a matter of weeks before bluebirds will be looking for nest sites again, and you want to be prepared. Early migrants may use the boxes as roost sites even before they are ready to nest.
My son, Greg, just sent me a note from his Houston-area home. A pair of eastern bluebirds is making a nest in a box that we put up along his fence line last year. This will be the fourth nesting of bluebirds in that box since we put it up. Greg’s note reminds me that it is time to clean out my bluebird boxes, evict the mice, repair boxes that need repairs and build new ones to replace those that are beyond repair. It really is time to think spring, even though it is snowing and the temperature is in the single digits as I write this. I will likely be on snowshoes as I do some of the field work, but it will be fun. Perhaps it will be a sunny day!
The rewards for building bird houses and maintaining them are immense. Unless mice or wasps take over a box, they are almost always used by some bird species, so you never know what is going to be in a box when you visit it. Mice can be evicted very easily, and removal of wasps doesn’t take much effort either. Box placement can teach us a lot about bird habits and habitat use. Over the years I have had dozens of bluebird pairs use boxes that I put up. I had a goal of producing 100 bluebirds in my boxes for a couple of years, and while the highest number I actually attained was 88, I learned a lot about bluebirds as a result. I actually got to know the idiosyncrasies of some individual bluebirds just by observing their behavior while I was around them. Some aggressively defended the box, swooping down at me when I would peek in. Others were nowhere to be seen but were undoubtedly watching me from a hidden perch.
In addition to bluebirds, I have had tree swallows, black-capped chickadees, house wrens and even great-crested flycatchers nest successfully in boxes that I initially put up for bluebirds. I once timed the visits of chickadees to their young in a box, and on average they brought in a green worm every three minutes plus or minus a couple of seconds! House sparrows have also tried to complete their nesting cycle in some of my boxes, but I refuse to let them nest successfully in any of my boxes and since they are unprotected, it is perfectly legal to remove their nests from the boxes if they get started in one. I have observed first-hand what house sparrows can do to bluebirds, so they are not welcome on my bluebird box trail. They should not be welcome in yours either, so keep that in mind if you decide to put up a nest box.
Eastern bluebirds are found throughout much of the United States east of the Rocky Mountains, which enabled a noteworthy situation last summer. During early July, Greg had a bluebird nest in a box in southern Texas, my dad had an active bluebird nest in a box here in Michigan’s northern Lower Peninsula, and I had two active bluebird nests at my Saginaw County home. Bluebirds from here to Texas – that was just cool!
There are several bluebird nest box designs that can be used successfully. For a selection of proven designs, I recommend that you visit the North American Bluebird Society website. In fact, that site is a good place to find lots of information about bluebirds and other cavity-nesting birds. When constructing the boxes, remember that bluebirds nest in woodpecker holes, hollow limbs, and other holes in trees and have done so successfully ever since there have been bluebirds. Therefore the boxes don’t have to be built to square, placed with a level or painted for presentation. They just have to have a proper-sized entrance hole, reasonable ventilation for hot summer days, a good roof to keep most of the water out, and be properly placed in good habitat, preferably in such a way that predators cannot get to the contents of the box. Building bluebird boxes is great fun for kids too. See an example of a blue bird next box design.
Yes, I am thinking about spring and bluebirds and wildflowers. It’s a great cure for the winter blahs! Won’t you join me?
