It may still be winter, but in our backyard, the Bewick’s wrens are already checking out the local real estate market. Last year we were lucky enough to host a pair of nesting chickadees in our backyard.
Watching birds select mates, build nests, and raise young is a wonderful education for children. Observing these processes is also a doorway into all kinds of great conversations about habitat, life cycles, the “birds and the bees,” and (sadly) sometimes death.
If, like us, you have not yet been fortunate enough to have a bird nest in one of your trees or shrubs, there are several species that will gladly accept the offer of a human-made nest box.
Knowing Your Customers
Birds build nests in one of four basic locations. Some birds prefer to nest in trees and shrubs. Most of them, like robins and goldfinches, build open-cup nests.
Other birds, like towhees, juncos, and some sparrows, prefer to nest on or near the ground. Some in this group also build open-cup nests just like the tree-dwellers. Killdeer, pheasants, and other ground-nesting birds make use of shallow depressions in the ground that can barely be called nests at all.
A third group, which includes kingfishers and puffins, actually nests in holes in the ground.
The fourth group, the cavity nesters, includes popular birdhouse residents like chickadees and wrens. These birds use holes—in trees, buildings, cacti, and birdhouses—to raise their young. According to The Complete Birdhouse Book, by Donald and Lillian Stokes, there are 86 species of cavity nesters in North America. Forty-one of these are listed as “easily attracted to birdhouses.”
Our family used the “super easy birdhouse” plans from The Complete Birdhouse Book. These houses attract a wide variety of birds and are ideal for the non-woodworker. Pieces are cut from one piece of lumber. A power saw is nice, but a handsaw will do. Other tools needed are a hammer, some nails, and a drill. With a little help, kids can easily assemble pre-cut pieces. Non-toxic wood glue will help keep the pieces together as kids hammer the nails in place.
NestWatch from Cornell Lab of Ornithology has several nest plans on its website. This plan is similarly “novice-friendly.” There is even a plan for building a chickadee house from recycled PVC pipe! If you have a little more woodworking experience, you can tackle some of the more difficult projects, or maybe dress up the outside of a nest box a little.
The one house specification you will want to note is the entrance hole size. This varies depending upon the species you are trying to attract (or exclude). A birdhouse book like the one mentioned above will have a list of species and corresponding hole sizes. You can also find that information on the NestWatch website.
Hanging Your Birdhouses
The ideal site for your nest box depends somewhat on the species you are trying to attract. Most birds are not terribly picky about height. However, they are selective about the habitat around the nest box. For example, chickadees prefer to nest in wooded areas and will happily nest in a box placed in or near a tree. Bluebirds, on the other hand, nest in open areas and are unlikely to use boxes in a wooded area. NestWatch has information on deciding where to place your birdhouses.
Is It Okay to Peek?
In a word, yes. For this reason, you’ll want to buy or construct houses that can be easily opened and mount them in places that you can reach.
Visiting a nest or touching a nestling will not cause the adult to desert the nest. And while we generally make areas near an active nest a “no-play” zone for a few weeks, many birds nest in surprisingly busy places. I recommend that unless you are an experienced nestbox monitor, you and the kids practice “look, but don’t touch” monitoring. Have children monitor boxes only under your supervision. Peeking in every few days in unlikely to deter nesting birds, but curious kids peeking in every hour will disrupt the nesting process. Also, don’t peek in the boxes during periods of bad weather (so eggs and babies don’t become wet or chilled) or just before fledging (so babies won’t be spooked into leaving the nest too early).
Keeping Out the Riffraff
I am a live-and-let-live sort of person, so the idea of actively discouraging any bird from nesting is outside my comfort zone. However, there are two nonnative species of birds that present an active threat to many native species in North America—the house sparrow and the starling. Both kill adults and young of other birds and take over nests. They begin nesting earlier in the spring than most birds, further limiting available nesting sites.
Cornell Labs has information about passive and active control methods to keep these species from nesting in your backyard. I’m not yet up for the active control methods, so for now we design our boxes with entrance holes that are too small for starlings or house sparrows. My neighbor puts out the welcome mat for our resident house sparrows, inviting them to nest in the two stylish birdhouses on her deck. She enjoys seeing the nesting birds and doesn’t mind their “pest” status. Ultimately, each family has to decide how to deal with this very real problem in its own way.
After each nesting season and again before nesting begins in the spring, remove nesting materials and clean any exceptionally soiled boxes with soap and water. Be sure to rinse thoroughly. This keeps mites, blowflies, and other parasites from building up and potentially threatening the next year’s nestlings. Some people plug the entrance holes in the winter to prevent overwintering mice and insects from infesting the nest. Others leave holes open for birds seeking shelter from bad weather. If you do plug up the holes, don’t forget to unplug them before the next nesting season. Happy birding!
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