Cavity nesting birds come in all shapes and sizes. Small songbirds, medium sized ducks, and even large birds of prey make up the 85 North American species that nest in tree cavities. These birds excavate their own holes, use holes excavated by other species, or use naturally occurring cavities that have resulted from decaying trees. You may have seen woodpeckers in early spring excavating their own cavities, while wood ducks, flycatchers, and owls use existing cavities.
Several cavity nesting birds have seen their numbers decrease in recent years, with habitat loss being a contributing factor. As trees are cleared to make way for development, so too are potential nest sites for these and other bird species. In many of our ESAs, city parks, and neighbourhoods, dead trees and limbs are removed due to safety concerns further reducing potential nest sites.
Some of the more common backyard cavity nesting birds found in our area are: woodpeckers, wrens, chickadees, and nuthatches. Depending on the habitat of your yard you may also find: swallows, bluebirds, ducks, and even owls nesting in cavities on your property. If your yard lacks dead, decaying limbs or you have removed them for safety reasons, many of these cavity nesters will readily accept a properly placed nest box of the appropriate size.
I like to make my own nest boxes with materials purchased from my local building supply store. Boxes are easy to make and the supplies needed are inexpensive to purchase. I have had great luck attracting cavity nesters to my yard following the free plans provided at 50 Birds.com. I find it incredibly rewarding to watch birds nest in a box that I made with my own hands. If you do not have access to tools, or just prefer the convenience of a ready made box that only requires hanging, nest boxes can be purchased from the same local independent retailer where you purchase your seed.
Now that the spring weather has finally arrived, cavity nesters are busy searching for potential nest locations. Survey your yard for any dead trees or limbs, assess any potential danger, and if safe to do so contemplate leaving them. If they have to be removed, or you have previously removed them, consider adding nest boxes to provide potential nest sites for any displaced cavity nesters.