Martins are entertaining creatures, however, and you’ll enjoy watching their antics in your backyard. You have the best chance of attracting martins if you put a house on the edge of a pond or river, surrounded by a field or lawn. Martins need a radius of about 40 feet of unobstructed flying space around their houses. A telephone wire nearby gives them a place to perch in sociable groups.
Martins nest in groups, so you’ll need a house with a minimum of four large rooms—6 or more inches on all sides, with a 2½ inch entrance hole about 1½ inches above the floor. Ventilation and drainage are critical factors in martin house design. Porches, railings, porch dividers and supplemental roof perches, like a TV antenna, make any house more appealing.
You can also make houses from gourds by fashioning an entrance hole and small holes in the bottom for drainage. If you use gourds, it’s not necessary to add railings and perches. Adult martins will perch on the wire used to hang the houses. Before you select a house, think about what kind of pole you’re going to put it on. Martins occupy a house ten to twenty feet off the ground. Some poles are less cumbersome than others.
Gourd houses are the easiest to set up. String them from a wire between two poles, from a sectional aluminum pole, or on pulleys mounted to a crossbar high up on a pole.
You can mount lightweight aluminum houses for martins on telescoping poles, providing easy access for maintenance and inspection. Because of their weight (more than 30 pounds), wood houses should not be mounted on telescoping poles. You’ll have to use a sturdy metal or a wood pole attached to a pivot post. The problem with this lowering technique is that you can’t tilt the house without damaging the nests inside. If you put your house on a shorter, fixed pole, ten to twelve feet high, you can use a ladder to inspect and maintain it.
Flycatchers
The great crested flycatcher and its western cousin, the ash-throated flycatcher, are common in wooded suburbs and rural areas with woodlots. Their natural nesting sites are abandoned woodpecker holes. Flycatchers may nest in a bird house if it is placed about ten feet up in a tree in an orchard or at the edge of a field or stream. This is a longshot, but well worth the effort if you are successful.
Woodpeckers
You can attract all types of woodpeckers with a suet feeder, but only the flicker is likely to use a bird house. They prefer a box with roughened interior and a floor covered with a two-inch layer of wood chips or coarse sawdust. Flickers are especially attracted to nest boxes filled with sawdust, which they “excavate” to suit themselves. For best results, place the box high up on a tree trunk, exposed to direct sunlight.
Try building a birdhouse for the other species of woodpeckers following the guidelines in this booklet. You might be surprised!
Owls
Most owls seldom build their own nests. Great horned and long-eared owls prefer abandoned crow and hawk nests. Other owls (barred, barn, saw-whet, boreal and screech) nest in tree cavities and bird houses.
Barn owls are best known for selecting nesting sites near farms. Where trees are sparse, these birds will nest in church steeples, silos and barns. If you live near a farm or a golf course, try fastening a nest box for owls about 15 feet up on a tree trunk.
Screech owls prefer abandoned woodpecker holes at the edge of a field or neglected orchard. They will readily take to boxes lined with an inch or two of wood shavings. If you clean the box out in late spring after the young owls have fledged, you may attract a second tenant—a kestrel. Trees isolated from larger tracts of woods have less chance of squirrels taking over the box.
Selecting a House
In the bird house business, there’s no such thing as “one size fits all.” Decide which bird you want to attract, then get a house for that particular bird. Look through any book or catalog and you’ll see bird houses of all sizes and shapes, with perches and without, made of materials you might not have thought of: recycled paper, gourds, plastic, rubber, pottery, metal and concrete. The proper combination of quality materials and design makes a good birdhouse.
Materials
Wood is just about the best building material for any birdhouse. It’s durable, has good insulating qualities and breathes. Three-quarter-inch thick bald cypress and red cedar are recommended. Pine and exterior grade plywood will do, but they are not as durable.
It makes no difference whether the wood is slab, rough-cut or finished, as long as the inside has not been treated with stains or preservatives. Fumes from the chemicals could harm the birds.
There’s no need to paint cypress and cedar, but pine and plywood houses will last longer with a coat of water-based exterior latex paint. White is the color for purple martin houses. Tan, gray or dull green works best for the other cavity nesting species. The dull, light colors reflect heat and are less conspicuous to predators. Don’t paint the inside of the box or the entrance hole.
Regardless of which wood you select, gluing all the joints before you nail them will extend the life of your bird house. Galvanized or brass shank nails, hinges and screws resist rusting and hold boxes together more tightly as they age.
Resist the temptation to put a metal roof on your bird house. Reflective metal makes sense for martin houses up on a sixteen-foot pole, but when it’s tacked onto the roof of a wood chickadee house, the shiny metal is more likely to attract predators.
Natural gourds make very attractive bird houses. They breathe, and because they sway in the wind they are less likely to be taken over by house sparrows and starlings.
Grow your own gourds and you’ll have dozens to choose from in the years ahead. If you don’t have the space to grow them, a coat of polyurethane or exterior latex (on the outside only) will add years to the one you have.
Properly designed pottery, aluminum (for purple martins only), concrete and plastic houses are durable, but don’t drop them.
Be sure to provide ventilation, drainage, and easy access for maintenance and monitoring. Concrete (or a mix of concrete and sawdust) offers protection other houses cannot: squirrels can’t chew their way in.
Design
How elaborate you make your bird house depends on your own tastes. In addition to where you place the box, the most important considerations are: box height, depth, floor dimensions, diameter of entrance hole and height of the hole above the box floor.
For the Birds · The Wunder Library — complete classics, free to read, with narration.