Why provide birdhouses? Habitat loss has driven some species away from former nesting areas. The right house can bring birds back home. "Habitat loss is the single greatest threat to our birds," said Adam Roberts, executive vice president of the conservation group Born Free USA. "You can help offset some of these threats by creating habitats in your backyard and community and get the whole family involved."
Birds' needs are straightforward: food, water and shelter. Bird feeders and birdbaths help provide the first two. Birds that can inhabit your birdhouse range from tiny sparrows to large crows. According to Debbie Arrington at the Sacremento Bee The world of birdhouses is divided into two parts: cute, decorative, often whimsical creations that appeal to humans; and functional nesting boxes that the birds will actually use.
This would explain why all my cute, whimsical birdhouses are devoid of birds. The bees love my cute empty houses. Now after writing this blog I am on my way to building better birdhouses, for I love my birds.
What birds want in a birdhouse?
Avian experts have spent decades researching that simple question — with a view to what makes the birds feel welcome, not necessarily what makes the prettiest backyard ornament.
Western bluebirds, wrens, titmice, nuthatches, woodpeckers, tree swallows and other house-hunting species will flock to plain, unfinished wood boxes — as long as they have the right location and dimensions.
They've got to be functional,". "We have a lot of cavity nesters, but not a lot of trees. ... If you put a box up, they'll find it." Be patient with a new home — it may take more than one season for birds to find their house.
The entry hole's size and the box's location are crucial, Hopperstad added. "If the hole is too big, it invites predators; rats and possums take the eggs. If the box is placed too low, snakes will get inside. Too big a hole also invites other (species of) birds to raid the nest. It's a bird-eat-bird world out there."
Wrens are the easiest to please; they don't mind people. But for their home, they need a small entry hole — only 1 ¼ inches across — to keep uninvited guests out.
When choosing a location, put some distance between the birdhouse and the bird feeder or bath. There's too much feathered traffic around feeders and baths for young families to feel comfortable.
Aged wood. Most cavity-nesting birds prefer weathered natural wood; it mimics tree trunks where they would otherwise nest. Use lumber at least 3/4-inch thick to help insulate the box from hot or cold weather. Rough, raw wood on the inside of the box gives babies a foothold to scramble up to the opening, so don't paint or smooth the interior. A few square inches of wire mesh or recessed grooves below the doorway also are helpful to baby birds trying to climb up.
Cozy space. Think of a hollow tree; that pocket is snug and deep. Cavity-nesting birds like their houses that way, too; 5 by 5 inches at the bottom is an ideal dimension for most species, with a depth of 5 to 6 inches below the entry and an overall height of 10 to 12 inches. Robins like an open-faced box — almost like a shelf — with no front wall.
Single occupancy. While martins like apartment complexes, other birds are territorial about their nests. They want a home of their own without noisy neighbors.
Slanted roof. That allows rainwater to run off easily. Make sure it extends over the entry.
That weathered look. Often, birds won't use a new house until it shows some age. Weathering also softens up the wood, making it easier for young ones to grab hold, so leave the house up year-round. A painted, decorated birdhouse may be cute, but unvarnished cedar, pine or redwood will get more use.
If you paint your birdhouse, birds aren't picky about color, but stay away from black or dark colors that absorb heat. Use nontoxic stains or varnishes.
A few extras. Proper ventilation and drainage are important to a happy feathered home. Make some slits or small holes just below the roof's eaves to let air in. Add some small drainage holes in the floor, at the corners or along the walls. A flip-top roof or side panel makes it easier to open the box for cleaning.
No perch necessary. Most cavity-nesting birds can cling to the outside of the box without aid, especially if it's natural wood. Perches actually help other birds or predators who may harass the nesters.
Nesting materials. Most songbirds won't reuse a nest the following year (although they have no problem reusing a house), which means they need new stuff each spring. Among favorite materials to line a new nest: moss, twigs, feathers, pine needles, shredded bark, soft grasses, yarn scraps, small pieces of fabric and hair (human, dog or horse).
Maintenance: Once a year, take the box down and clean it out. Remove the old nest. Scrub with a stiff brush and a mild bleach solution to kill mites or other parasites.