by Esther Lutz, East Central Illinois Master Naturalist for University of Illinois Extension in Coles County
Spring is in full swing, and the birds are singing! Not only are the winter regulars setting up territories and seeking out mates, but the migratory species are also returning to our backyards from their wintering grounds to prepare for the hectic nesting season.
Different species of birds have different requirements when it comes to the types of shelters and surroundings they like. Some birds will nest almost anywhere, while others are more picky. The scarcity of suitable nesting sites can sometimes prevent many species from moving in to what would otherwise be excellent habitat for them. And when natural homes are hard to find, you know what that means -- the birds go house-hunting!
Just what kinds of birds would we like to have raising families in our yards? Because the various species have specific needs, it is often wise to provide a variety of nesting box types and sizes in order to attract the most species. These little guys and gals can be choosy, and will often inspect several options before committing to one particular house in one specific location. There are a few basic things we must consider when deciding what kinds of houses to put up in order to attract even the most common backyard birds.
What types of shelter are best? It is very helpful to be aware of the species requirements with regard to the right height from the ground, the size of the entrance hole, and the size of the house itself. It is always wise to consider the needs of the species we are trying to attract. If we want bluebirds but we put up a nesting box that is more appropriate for chickadees or wrens, then we're probably going to get chickadees and wrens. Consulting a birdhouse chart (found in many birding books and websites) that lists the dimensions, hole diameters, and height above ground can be very helpful. The size of the "front door" (entry hole) is very important as it must be large enough for the bird to enter but small enough to stop larger birds and predators from invading the nest. Be sure that all of your birdhouses have no front landing perches and if they do, remove them. These perches may give predators an unfair advantage when raiding the nests, and the birds don't need them.
Are the brightly colored and decorated birdhouses we find in the stores okay to use in our yards? Not all birdhouses on the market are suitable for nest-building. Many are very cute and look like little decorated houses or whimsical structures. There may be nothing structurally wrong with these, but they are usually put to better use as indoor decorations to enjoy. The best birdhouses for wild birds are made of wood, with ventilation holes around the top and drainage holes in the floor. There should also be a roof overhang by one or two inches to shade the entrance hole and protect it from rain. Painting or staining the houses brown or green or other earth tones helps them blend in with the natural surroundings and seems to be preferred by most birds. (An exception to this may be purple martin houses which are sometimes made from dried gourds or aluminum, both painted white to reflect the sun's rays and keep the houses cooler.)
Where is the best place to locate the birdhouses? It is a fact that each bird species has its own habitat requirements, and this includes the place it will choose for nesting. Chickadees, for example, prefer that their houses be in a stand of small trees or shrubs, or in a thicket. Bluebirds require a habitat where insects are plentiful for eating and for feeding their young, so the best location for them would be an area facing or surrounded by open fields. House wrens will nest in lots of different locations, but a single house hanging from a tree in an open yard will often be occupied in short order. (Our house wrens often choose a nest box close to our house and seem to actually enjoy being around us as we come and go.) Purple martins like to live in communities with each other and choose "apartment-style" houses placed high on a pole or in groups of multiple nesting gourds in the middle of open spaces in lawns or fields. The best way to attract the most species is to offer several different types of houses in various locations so the different birds can choose the home that fits their lifestyle. This approach gives the best chance for attracting the most tenants during the nesting season.
It is also a good idea to face the house away from the prevailing winds, and near a tree or bush. The adult birds will often use a branch as a handy perch to watch for danger and to make sure that it is safe to fly into the house or feed the young. Keep in mind that a house may be occupied soon after it's put up, or it may take weeks, months, or even years before we see a prospective "buyer." If a birdhouse is not used during an entire spring or summer, it may be wise to move it to a different location.
When is the best time to set up my birdhouses? Nest boxes may be put out in the last days of winter or in the early spring so that they are up and ready for inspection as soon as the need arises. Now is the perfect time to place houses if they haven't been set out already. Because birds will nest all summer long and may raise two or more broods (for which they make a new nest each time), it is never too late to set up housekeeping for them. The houses can also provide protection from the elements during fall and winter. Therefore, any season is the right time to establish bird housing.
Do we need to put nesting material in the box? Absolutely not. The birds will take care of this chore all by themselves. We can, however, offer loose nesting materials in a nesting basket (available from bird supply places), or simply an old suet feeder hung on a fence or tree branch, near the birdhouse. Materials include cotton fibers, cut dried grass, pet or human hair, fabric strips, short sticks, string, yarn, and horse mane and tail combings (all with lengths less than six inches long). Avoid dryer lint which may fall apart in the rain. By providing these things, we can help ensure that the baby birds grow up in the softest and driest nests, giving them the best chance at survival.
There is something special about providing a bird-friendly habitat that supports new life. Each species is aware of its own needs, and bird parents will settle where they can provide for their young with the resources at hand. Witnessing the courtship, nesting, and fledging stages of birds is one of the best ways to appreciate the beauty of the natural world. And once in place, birdhouses can bring hours of pure enjoyment to those lucky enough to have such vibrant miniature communities in their own backyards.