Forestry & Wildlife
Bluebirds, robins, chickadees, titmice, wrens, and purple martins adapt easily to using bird houses. They will choose rural or urban yards alike where there is a small patch of suitable habitat. This may consist of homemade bird houses and berry baskets of hair, moss, cotton balls, and yarn. Or, it may be a patch of wild garden and trees. The birds’ nest building and food gathering provide hours of entertainment to armchair bird watchers.
Nest Box Construction
Lumber. Almost any grade of untreated lumber can be used to build nest boxes. Several types of wood, however, are more durable and desirable. Treated lumber should not be used for nest boxes. The most durable woods include cypress, cedar, and redwood. Pine, although less durable, is easier to work with and somewhat less expensive than other wood. Exterior-grade plywood can also be used; it is recommended for roof boards, no matter what lumber is used to construct the nest box. Lumber should be at least 3⁄4-inch thick to provide insulation for the birds. Nest box dimensions and height for placement are shown in table 1. Construction details of some boxes are shown in figures 1 to 4.
Table 1. Nest Box Dimensions and Heights for Box Placement
|Species||Box Floor (inches)||Box Depth (inches)||Entrance Height (inches)||Entrance Diameter (inches)||Box Height (feet)|
|American robin**||7 x 8||8||-||-||6–15|
|Eastern bluebird||4 x 4||8–12||6–10||1.||4–6|
|Chickadee||4 x 4||8–10||6–8||1.∕8||4–15|
|Tufted titmice||4 x 4||8–10||6–8||1.||5–15|
|Crested flycatcher||6 x 6||8–10||6–8||1.||5–15|
|Phoebes**||6 x 6||6||–||–||8–12|
|Brown-headed nuthatch||4 x 4||8–10||6–8||1.||5–15|
|White-breasted nuthatch||4 x 4||8–10||6–8||1.∕8||5–15|
|Prothonotary warbler||5 x 5||6||4–5||1.∕8||4–8|
|Barn swallow**||6 x 6||6||–||–||8–12|
|Purple martin||6 x 6||6||1–2||2.||6–20|
|Downy woodpecker||4 x 4||8–10||6–8||1.||5–15|
|Hairy woodpecker||6 x 6||12–15||9–12||1.||8–20|
|Pileated woodpecker||8 x 8||16–24||12–20||3 x 3||15–25|
|Red-headed woodpecker||6 x 6||12–15||9–12||2||10–20|
|Yellow-bellied sapsucker||6 x 6||12–15||9–12||1.||10–20|
|Carolina wren||4 x 4||6–8||4–6||1.||5–10|
|House wren||4 x 4||6–8||4–6||1.||5–10|
|* Height of entrance above nest box floor.|
|** Use nesting shelf with open front.|
Painting. Painting is not necessary except for purple martin houses or others made of soft wood. Use a water- based exterior latex if the box needs paint. Do not install the box for at least 2 weeks after painting. Light shades of green, gray, and tan are the best choices for nest boxes. Only light colors should be used. Dark colors may cause boxes to overheat and injure eggs and young. Martin condominiums, which are usually placed in open areas, may be painted white to reflect even more light.
Drainage and Ventilation. Boxes should be ventilated by leaving narrow spaces between the roof and sides or by drilling two 1⁄4-inch holes in the sides. Drainage holes may be drilled in the floor or 3∕8-inch can be cut away from each corner of the floor (figure 2).
In many urban areas it is difficult for birds to find nesting materials. Light materials placed in hanging berry baskets will be used readily by yard-nesting songbirds. Attach berry baskets to sturdy limbs with nylon cord. Place them out of reach of cats and dogs. Light materials such as dog hair, moss, cotton balls, yarn, and string can be placed in the baskets, and birds will use them throughout the breeding season.
Tenants for Your Bird Houses
Bluebirds. Eastern bluebirds are one of Alabama’s most beautiful year-round residents. The adult males are brilliant blue above and reddish or rust below with a white underbelly. Females are drab versions of the males.
Populations of these birds have grown rapidly over the past few years, mostly in response to people constructing and placing nest boxes. Bluebird trails where boxes are placed along paths through good bluebird habitat have been established in many states. This partially compensates for the loss of preferred nesting sites such as wooden fence posts and cavity trees. Before bluebird boxes were erected in great numbers, starlings and house sparrows reduced the bluebird population by competing for and winning available nesting sites.
Bluebirds usually nest along woodland edges of open fields or other open areas. They are often seen along farm fields, golf courses, and pastures. Nest boxes placed along the edges of these areas are preferred nest sites. A good supply of insects and berries are essential to this songbird. It does not usually feed at bird feeders.
Nest boxes should be placed 3 to 5 feet above ground and at least 25 feet from the nearest tree. Nests should be removed from the boxes after each group of young birds (brood) has left the nest (fledged).
Robins. American robins are not cavity nesters; they are platform nesters. Robins winter in Alabama but generally nest from central Alabama northward to Alaska. Migrating robins pass through Alabama in March on their way to northern nesting grounds.
Robins are fairly large songbirds that are often seen feeding on moist lawns. This bird population has actually grown in response to human development of habitats considered typical for robins. Now robins are found in a variety of habitats ranging from deep woodlands to inner city parks, all of which are ready sources for the fruits, berries, insects, and earthworms robins eat.
Robins’ nests are not neat. They build nests of grass, twigs, and mud in orchard trees, shrubs, and on buildings. Highly compatible with human developments, robins will use man-made nesting platforms when available.
Nesting platforms should be placed on a tree or on a pole near a tree 6 to 15 feet above ground. Fairly open areas with protective shading are preferred.
Carolina Chickadees. Carolina chickadees are friendly little birds that sing year-round. They have buzzyChickadee-dee-dee-dee calls. Their black caps and bibs, white cheek patches, gray backs, and pale undersides are easily distinguishable from other local songbirds.
Chickadees are not migratory. And, they are common at the feeder. They live with equal ease in woodland habitats and in close association with human beings. In hot summer months, however, chickadees will often retreat to the cooler moist woodlands.
Chickadees consume numerous farm and garden pests. They search from daylight to dusk for their primary summer food items—insects. They also feed on seeds, berries, and other fruits.
Chickadees nest in decayed stumps, abandoned nest holes, or in nest holes they have excavated. They build nests of moss, feathers, and other soft materials. Nest boxes for chickadees should be placed 6 to 15 feet above ground near several large trees. Protective shading should also be provided.
Tufted Titmice. Common in most yards, the tufted titmouse is often seen with Carolina chickadees. And, like the chickadee, it feeds heavily at feeding stations. A year-round resident of Alabama, the tufted titmouse supplements its heavy insect diet with seeds and berries. The tufted titmouse is mostly gray with a gray tuft or crest on the top of its head, white underparts, and very light orange sides. The song of the tufted titmouse is a loud and fairly rapid peter, peter, peter, repeated regularly
In many ways similar to the chickadee, the tufted titmouse frequents a wide variety of habitats from woodlands to residential areas. A cavity nester, too, it often nests in deserted woodpecker cavities, natural tree cavities, and in nest boxes; it will even excavate a cavity if soft wood is available. Nest boxes for titmice should be placed 4 to 10 feet above ground on posts or trees located at woodland edges.
Wrens. Carolina wrens and house wrens are small, nonmigratory songbirds that can be seen throughout the year in Alabama. Of these two birds, Carolina wrens are an especially desirable yard species because they tend to sing year-round. Their resonant tea kettle song is unmistakable. The distinct white eye lines and buff yellow underparts are characteristic of these wrens. The smaller house wren is more drab, with few distinguishing marks. The song of this species is bubbly but otherwise less distinctive than that of the Carolina wren.
Wrens feed almost exclusively on insects, spiders, and other invertebrates, but, in winter, Carolina wrens will sometimes use bird feeders stocked with small black sunflower seeds or suet.
Carolina wrens and house wrens are attracted to thickets and brush piles bordering open areas. They will often nest in yards near these brush piles. If nest boxes are not available, these birds will nest in almost any available cavity. Carolina wrens are notorious for nesting in any available spot, including hanging potted plants and the pockets of clothing left hanging on the clothesline.
And, wrens are not choosy about man-made nesting places. Clay flower pots with slightly enlarged drainage holes provide excellent nesting cavities for wrens when placed flush with a vertical surface. Coconuts with suitably sized entrance holes (11⁄4 inches in diameter) are also readily used.
Wrens frequently construct dummy nests in the immediate vicinity of their actual nest sites. These dummy nests may serve to confuse predators or to reduce the chances of other birds nesting nearby.
Wren houses should be placed 6 to 10 feet above ground on poles. Place the poles in open areas near brush piles or thickets to attract the most wrens.
Purple Martins. Although not generally considered a songbird species, purple martins are easy to attract and a favorite yard species in the southeast. These birds are noted for their tremendous appetites for mosquitoes and are well appreciated in most communities.
The fairly large, shiny, bluish-purple martins are migratory, spending the winter in South America. Purple martins send out scouts in mid-February to March to search out potential nest sites; the remaining colony members arrive later. Nest boxes must be erected before the scouts arrive to attract purple martins for a particular season.
Purple martins inhabit open woodlands and field edges, usually near lakes or ponds. They feed on insects. Preferred nesting sites are woodpecker holes, natural tree cavities, caves, and man-made martin condominiums and gourd houses.
Purple martin houses should be placed on poles in fairly open areas 15 to 20 feet above ground. These houses should be taken down and cleaned at the end of the nesting season and then put back in early February before the scouts arrive.
Predation and Competition
In recent years, starlings and house sparrows have developed reputations for competing with cavity nesters for nest sites. Native birds that can use cavities with small entrance holes (less than 11⁄4 inches in diameter) are less likely to suffer from competition from house sparrows. Starlings will prey on nestlings of other birds if perches are placed on the nest boxes or if entrance holes are large enough to allow starlings to reach down into nest boxes. When large populations of sparrows or starlings are present, nesting structures should be located at least 1,300 feet from human dwellings, barns, or feedlots.
Landscaping and Water Availability
Besides providing nest boxes for songbirds, many homeowners want to do more to attract birds to their yards. Managing the area around your home for birds is simple, especially if traditional gardening is already being done. Plan for available food plants, feeding stations, adequate plant cover, nesting sites, and a year-round supply of water.
For More Information
For specific information on managing for songbirds, see Garden Birds: How To Attract Birds To Your Garden, by Noble Proctor, Rodale Press.
The songbirds mentioned here are only a few of the many yard-nesting species found in Alabama (table 1). To find out more about the nesting requirements and construction of nest boxes for other native birds, see the following publications:
Building Birdhouses and Bird Feeders: A Family Workshop Book, by Ed and Stevie Baldwin, Doubleday & Company, Inc.;Attracting, Feeding, and Housing Wild Birds—with Project Plans, by Phyllis Moormon, Tab Books Inc.