Read an Excerpt
By Charles Self
Dover Publications, Inc.Copyright © 2007 Charles Self
All rights reserved.
WHAT THE BIRDS LIKE
We begin this series of projects by looking at what a birdhouse needs most, from a bird's point of view. In general, my aim in this book is to ensure that the birds are happy with your efforts.
Snugness. This one is simple enough. A snug birdhouse has just enough room for the nesting materials, the bird, and the young birds, and not much extra space, but is not so cramped that there's no room for several babies and the parent. Birds have size needs (just as we do), and they react, live, and reproduce better when those size needs are met. You'll find size requirements for most types of desirable nesting birds in this book, and changing a few sizes, sometimes only one, can make a single birdhouse design suitable for a number of birds.
General comfort. Protection from wind, rain, and snow—as well as sleet and hail—is a desirable feature, with the opening oriented to the direction preferred by the species of bird. Ventilation is an important factor here. Ventilation slots or holes cut well up in the birdhouse help to maintain air movement with the front opening and with floor drain openings.
Slow reaction to temperature changes. Probably better than slow is "slower" reaction to temperature swings. This means you don't want a roofing material that heats up so fast it cooks the birds or makes them ill from the heat. The same with cold. Birds can stand a reasonable amount of cool, but we don't want them turning gelid on the nest. Use housing materials that retard heat movement in either direction. That doesn't necessarily mean you need to build and insulate a huge birdhouse, but using natural materials such as solid wood is a start. Proper location, out of direct sun and wind, is another salient point.
Dryness. Easy enough. For those birds that insist on enclosed nesting spaces, try to provide corner or other draining in the bottom of the birdhouse for any incidental water entry, and orient the house so openings are not in direct line with driven rain or snow or ice.
Protection from predators. I don't suggest you shoot your neighbor's cats, but you want to make it more difficult for cats and snakes to gain entry or even access to the birdhouse. Leave off the exterior perches, for a start. Mount the house on a slick pole, as far up as the desired species will accept. Use predator guards—a cone of light metal wrapped around the pole, wide side down—where possible. These keep snakes from slithering up the pole.
Suitable distance from the ground to emulate natural nesting spaces. Some birds like 3, 4, 5 or 6 feet while others prefer 20. There is seldom much nest interchange (of course, most of the birds that nest low are smaller, while those that nest high tend to be larger—like all generalities, that one has major holes, I know).
Ease of entry. The house needs to be easy for the bird to get into and out of, while also being difficult for snakes to enter. It's always nice when you can confine entry to one or two bird species. This sometimes works, but it often doesn't. Keep the entry holes as small as possible for the species desired, and rough up the exterior around the hole so the bird's claws have something to grip. You might place a small perch inside the entry hole, too.
Appearance. Birds are a bit like auto and truck drivers. Don't startle them and they're a lot happier. Give them something too shiny, and they tend to flutter off. They may or may not return. Make them a birdhouse that fits into the natural scheme of things, and they're more likely to check it out and stay. Anyone who has ever seen bluebirds house-hunting knows that this works. I've seen bluebird pairs build in two newer houses, only to go down the fence line to the most dilapidated—to human eyes—derelict chunk of redwood boards around, and set up housekeeping in the near wreck more times than I want to count.
Getting the size right is of importance if you're aiming to attract birds, though most birds are willing to adapt to slightly unsuitably sized nesting areas. The chart on the next page gives some sizes for birds that we generally welcome in yards and around houses.
A cautionary tale: there are many more welcome birds, and there are some cautions about the birds listed in the chart, especially the larger woodpeckers, such as the flicker and the red-headed. Both of these birds, once established, can be amazingly destructive of property and very difficult to discourage. On a personal note, I've had lots of damage to my woodworking shop created by flickers enlarging openings in the eaves, and on the soffit and fascia, in order to get into the attic area of the shop for nesting purposes. I have yet to find an effective way to seal the area and evict the birds, and the larger holes have brought a plague of squirrels with them. They also damaged one corner of that house badly, forcing replacement of some siding and a couple of corner boards.
There are many more birds that you will find flitting around a yard, including doves and wrens, some sparrows, chickadees, nuthatches, phoebes, bluebirds, swallows, and many of the woodpeckers, including the downy and the hairy. Not all are birds that nest in houses. Some birds are desirable, while others are less so. Starlings are a plague on many feeders and around yards, where they adapt quickly to conditions favorable to almost any small birds, too often ousting the more favored birds.
Birdhouses provide spring care for birds and a nesting site that helps them keep their numbers up.
When you say "C'mon to my house" to birds, you're making a commitment that helps keep a continuing natural balance on things; gives you enjoyment in constructing wood projects; gives you an excuse to collect tools that are handy for other projects, non-bird related; and also gives you a shot at great enjoyment in watching their numbers increase. It's hard to describe the enjoyment you'll get when you note a declining species (which bluebirds were, some twenty years ago), having several batches of chicks each year, teaching them to fly, feed on their own, and generally introducing them to bird life. But it is better than just good.CHAPTER 2
MATERIALS: WOOD ISN'T ALL OF IT
There are a limited number of truly useful birdhouse woods, though you can actually use almost any wood, including a multitude of exotics that has a reasonable chance of surviving more than two seasons out-of-doors. But the expectation that a birdhouse should last only a couple to three years is not a good one, as it may take that long to attract birds to the nesting area. Some woods do well when painted, others do well when left alone. Of the dozen or so suitable woods, pine is probably the cheapest in most areas, but woods such as walnut and white oak give some unusual talking points, as do woods such as mahogany. On a personal basis, I prefer easily worked woods for birdhouses, which tends to mean using sharp tools and softwood, either a pine, cedar, or cypress. Some are better than others at what we need. Pines do not last for an exceptionally long time, though I've got one pine birdhouse up in Virginia (south central region) that has been in place for over five years. It is unfinished and doing fine. There are also some redwood bluebird houses there that are outlasting the locust fence posts they were originally hung on, nearly sixteen years ago.
I've worked to keep open end grain from standing vertically in my plans (sometimes, as with backs, it is unavoidable), which helps keep water from penetrating and starting a destructive freeze thaw cycle in winter. That helps any wood, regardless of its durability. Otherwise, durable woods such as some cedars, cypress, redwood, walnut, white oak, and others last the longest.
I'm not providing furniture-makers' detail on woods here, as that is unnecessary, as is providing information on nondurable hardwoods. Photographs of some of the woods described in this chapter have been reproduced in full color on the inside front cover.
Alaska cedar is the starting point for this group of durable softwoods. Growing from the Pacific Coast region of North America from southeastern Alaska down to southern Oregon, Chamaecyparis nootkatensis is straight-grained and fine-textured. The sapwood is white shading to yellow, with a bright yellow heartwood. Often called yellow cedar, it is taken from a tree about 80' to 100' in height. There is little difference in appearance of heartwood and sapwood. Alaska cedar is moderately heavy, very resistant to decay, and is moderately hard. After seasoning, during which it shrinks very little, Alaska cedar is quite stable. It is not an aromatic cedar (its odor is mildly unpleasant, but after cutting, it fades to a potato-like smell). It works easily with both hand and power tools. For birdhouses, Alaska cedar is an excellent choice.
Incense cedar, Libocedrus decurrens, is from a tree 80' to 150' in height, and 3' or more in diameter. The sapwood is white to a cream and the heartwood is a light brown, often tingeing toward red for a pink overall hue. The wood has a fine, uniform texture, and a spicy aroma when it is cut or sanded. Unlike Alaska cedar, and more like the remainder of American cedars, incense cedar is light in weight, fairly low in strength, with low shock resistance and not a whole lot of stiffness (for a wood: don't whack yourself on the head to test hardness or see if the board flexes). Shrinkage is modest, and there is little checking and warping during seasoning. Incense cedar is locally low in cost, if you can accept its pecki-ness (localized pockets of decay that do not spread after the wood is dried). The wood works easily with conventional (tool steel) tools and with carbide tools. It makes superb small box material, including boxes that become birdhouses.
Port Orford cedar, Chamaecyparis lawsoniana, has heartwood that is light yellow shading to a pale brown. Sapwood is thin and hard to discern from the heartwood. The wood is non-resinous from a tree up to 160' in height and 5' in diameter. The wood is fine-textured, with generally straight grain, and has a pleasant and spicy odor. Port Orford cedar is superbly resistant to decay, moderately light in weight, and is stiff, moderately strong, and hard. The wood works easily with conventional hand and power tools. It is excellent for birdhouses.
Red cedar, Eastern, is aromatic cedar, and grows everywhere in the East except Maine and Florida. Juniperus virginiana is the major species of Eastern red cedar, but in some South Atlantic and Gulf Coastal Plains areas, you will also find Juniperus silicicola. Both are sold as red cedar without further identification. The tree is small, usually not more than 40 feet tall. The heartwood of the red cedar is bright red, sometimes almost purple, tending to a duller red. The thin sapwood is almost white, and clearly defined. The wood is moderately heavy, moderately low in strength, and is hard. It seasons well, has high shock resistance, and low stiffness, and a tight, fine texture. The grain is said to be straight, but after cutting hundreds of red cedars, I've yet to see any run straight for much longer than a couple feet. The wood is easily worked with conventional tools of all kinds, but will deposit lots of pitch if not seasoned well. Regardless, it lists as a non-resinous wood among botanical classifiers. The many, many knots deflect the grain. Red cedar is an excellent birdhouse wood.
Red cedar, Western,Thuja plicata, is also called canoe cedar, giant arbor vitae, or shinglewood. The tree may be 160' (and more) tall and 4' thick. The aroma is pungent and attractive. Heartwood is reddish brown to dull brown; sapwood is nearly white, and narrow. The wood is straight, but has a coarse, uniform texture. Shrinkage is slight, and the resulting wood is light in weight, moderately soft, low in strength. Heartwood is exceptionally resistant to decay. Western red cedar works easily—most red cedar shakes are hand-split—with all conventional tools, both hand and power. It is excellent for birdhouses.
White cedar, Northern and Atlantic, are usually clumped together at sales time. Northern white cedar is Thuja occidentalis (also called, simply, cedar, and arbor vitae). Southern white cedar is Chamaecyparis thyiodes (also Southern white cedar, swamp cedar, and boat cedar). The trees are about 65' tall, and not over 24" in diameter. White cedar heartwood is light brown, and the sapwood is nearly white, and forms only a thin band. The wood is lightweight, soft, and not strong. Shock resistance is low, but shrinkage during seasoning is low, and the wood is stable afterwards. This cedar takes paint well—most others require a coat of shellac to prevent bleed-through of resins—and like the rest of the cedars, works easily with conventional tools, both hand and power. Heartwood is exceptionally durable, so the wood is superb for birdhouses.
Cypress is also called baldcypress, Southern cypress, red cypress, yellow cypress, and white cypress. It is a deciduous—leaf-dropping—softwood, of medium size rarely reaching 145' in height, and more often 65' to 130'. It has a buttressed trunk—cypress knees are famous—that may be as much as 5' in diameter. The wood is moderate in cost within much of its range. Current early-growth heartwood cypress is not as durable as old-growth, but still lasts extremely well. I built some cypress birdhouses recently, and expect them to endure for many years. Cypress is another tree with only a small sapwood band, which is nearly white, contrasting strongly with the light yellowish brown to dark reddish brown, brown, or even chocolate of the heartwood. Taxodium distichum is moderately heavy, moderately strong, and moderately hard. It's easy to work with conventional hand and power tools, and shrinks a bit more than cedars, but still within a very small range. Durability (decay resistance) ranges from truly great for old-growth cypress to moderately good for new-growth materials. Cypress is great for boxes of most sizes: of course, boxes include birdhouses and nesting shelves. It is not always easy to find, and I've never seen it in any of the big box stores for home builders. You need to locate a wood dealer—oddly enough, this softwood is often sold by hardwood dealers.
Pines are woods most of us know, both as woodworkers, and as people living in homes with wood products. Pines are more prolific now than any other wood and are probably used for more things than most other woods. Some pine species are very soft and low in strength, though still strong enough for building construction. They accept shaping amazingly well, so a great many items from birdhouses to doors are produced from pine today. In addition, pines come in species that are almost as hard as a mid-range hardwood (many of the yellow pines) that do not take nails easily, and that are not as easy to shape, but that are wonderfully strong and useful in many ways, again, including birdhouse construction.
Pine, Eastern White, Pinus strobes, is also known as white pine, Northern white pine, Weymouth pine, and soft pine. The tree may be 100' in height, and 30" through the trunk. Heartwood is light brown, often tinged red, and turns considerably darker when exposed to light and air. The wood has reasonably uniform texture and is straight-grained. It kiln dries easily, with little shrinkage, and ranks quite high in stability. It is also easy to work with all sharp tools, and is easily glued with almost all woodworking adhesives. Eastern white pine is lightweight, moderately soft, moderately low in strength, and has a low resistance to shock. The hobby woodworker finds that it works easily with conventional tools, but resin tends to build, even from thoroughly dried white pine. It takes finish well, especially if you seal—with shellac—all the knots. Cleaning blades and bits frequently helps prevent burning. When aged, Eastern white pine is a pumpkin color, and often derives a name—pumpkin pine—from that color. White pine is one of the moderate-cost woods and comes in many grades. On top of all that, it's the fastest growing tree in its range, often spurting up a foot and a half a year.
Pine, Pitch, Pinus rigida, is the pine most closely associated with hollers and hardscrabble. It is a resinous wood with a brownish red heartwood. The sapwood is thick and a light yellow, while the wood of the pitch pine is moderately heavy fringing toward heavy, moderately strong, stiff, and hard, with moderately high shock resistance. Shrinkage is moderate and it is good for birdhouses ; expect it to last several years without finishing. The wood works easily with conventional hand and power tools, but the build-up of resin is quick and must be cleared from blades frequently.
Pine, Ponderosa, Pinus ponderosa, is another large tree, often reaching 230' in height, with a trunk about 30 inches in diameter. This is a yellow pine, similar to white pines in appearance and properties. The heartwood is a light, reddish brown, and the wide sapwood band is nearly white, varying to pale yellow. It is usually straight-grained, and has modest shrinkage during drying. The wood is uniform in texture, with little tendency to warp or twist. It works very nicely with conventional hand and power tools and resin build-up is within reason (it always pays to keep clearing resin when working with pines, cedars, and other sometimes non-resinous woods that have sticky sap). Although it is used mainly for lumber, this clear wood makes good birdhouses. Ponderosa pine should be painted or varnished for birdhouse use.
Excerpted from Easy-to-Build Birdhouses by Charles Self. Copyright © 2007 Charles Self. Excerpted by permission of Dover Publications, Inc..
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